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scott mims
02-28-2015, 12:49 AM
Ok...... Is it strictly the "turning" of the tuner that does what "it does" to accuracy or does the weight of the tuner play a part in it?
Also has anyone tried putting washers (rubber or other material) up and down a barrel to see if it would have the same outcome as a tuner on the end of the barrel? I'm sure you would have to keep a eye on the rubber washer so when the barrel heats up they wouldn't melt 😄

But seriously has anyone done that test before.... One thick washer and go up and down on the barrel to find the tune or several different washers up and down the barrel....... Sorry for the strange question.........it is February after all 😄

mwezell
02-28-2015, 06:50 AM
Scott, in a nutshell, weight at the muzzle changes both the frequency and amplitude of vibration, vs. no weight(tuner). Moving that weight makes changing the frequency possible. The weight creates more amplitude, effectively slowing the muzzle and making it's movement more vertically biased. The benefits here are longer and more pronounced dwell times at optimal bullet exit points, in turn, yielding a wider tune window. Some use a tuner for this benefit alone, but still tune with powder charge/seating depth..etc.

Moving the tuner OTOH, is essentially doing the same thing as tuning with traditional methods. That being, timing bullet exit with the muzzle being at a node, producing optimum tune or accuracy for a given setup. A huge benefit here is the ability to tune at the bench rather than changing loads.

I go to matches pre-loaded and only adjust the tuner, if/when needed, to maintain tune..the same way as if I were changing loads to keep the gun/ammo in tune. I've been doing it this way since I first started using tuners several years ago, now.

Tuners are much, much easier to use than to understand. They take very little movement to maintain tune. The most common misconception people make with tuners is assuming that they need big adjustments. If that were true, they would likely over complicate matters. In fact, that's far from the case, though. They are extremely easy to use..IMO, much, much easier than learning to tune by traditional methods. Different tuner styles and variables such as barrel contour play a role in this, but typically, movement as little as a single mark on the tuner is enough to maintain tune throughout the day, and often, due to the wider tune window that the mass at the end of the barrel gives...no adjustments are needed at all. My tuners have 32 hash marks and are threaded .900x32tpi, so, we're literally talking about being able to see on target, .001" of tuner travel. It's very typical to go from completely in tune, to completely out of tune in about .004", or 4 marks with my tuner. I'll include a link to my tuner page. There's some good reading there should you wish to view it.
Here's the link. The pics are old. The cf tuner(top) is designed to be threaded onto the barrel. The bottom pic is a rf tuner, made to be clamped on.
http://www.ezellcustomrifles.com/home-3/pdt-tuners/


As for rubber washers etc., I can only say that while some have claimed good results, I have not done enough testing to be conclusive. I have wrapped a barrel with .080" thick heat shrink tubing...It didn't work for me.

Boyd Allen
02-28-2015, 10:52 AM
Years ago, I did some tuner testing. None of if contradicts what Mike wrote, but I will add one thing. The rubber damps vibration. This is demonstrable by tapping on a free floated barrel with a small piece of metal. Not all things rubber or plastic are created equal in this regard. IMO heat shrink tubing was created for other purposes than damping vibration. I have used Sims Laboratory's Deresonator for this purpose, and it is quite effective in damping vibration. Of course its placement on the barrel is another matter, but the damping is quite evident by the sound with and without. Essentially there are two issues here, barrel vibration frequency and amplitude, which are influenced by tuner position and weight, and the damping of spurious vibration that may originate from the action of the striker assembly and bolt in the action. (Yes this is conjecture.) As to the proper way to use a tuner, one of the most successful tuner users in CF short range benchrest, Gene Buckys, tells me that he sets his tuner for the broadest node that he can find, after first tuning his rifle without it, and then from that point on, he tunes in the normal manner, as if he were not using a tuner. He told me that he specifically does not want to move a tuner during a match. My point in mentioning this is not to say that one approach is more correct, but rather to point out that successful shooters vary in their opinions as to how to best use their tuners. From what I hear, preloading is mostly done by score shooters, and sees little use in group. I think that it may be that the .30 BR lends itself to this more than the 6PPC. Getting back to Gene Buckys for a moment, he says that the primary advantage of tuners is that they broaden nodes.

mwezell
02-28-2015, 12:14 PM
Thanks Boyd. I agree. I think the biggest hurdle standing between more widespread use of tuners is weight in lv class. Without adding mass to the overall barrel, tuners are much less effective. IOW, it needs to be heavy enough to work...OR, as we've discussed, barrels need to be more tuner friendly. I still plan to hinge a barrel pretty soon. I'll keep you posted on what I find, but time has been very short of late and the weather has been uncooperative, to say the least.

There are exceptions to virtually everything in life, and in br, but I can't think of anyone who has given tuners serious consideration that has regretted using them. Weight keeps a lot of people from trying them.

Whether one uses a tuner like Gene, strictly for the wider nodes, or like most of the rest of us, to adjust, they have proven to me to be a valuable tool where weight allows. Frankly, while I'm not going to knock what works for one of the best shooters on the planet, I don't understand the notion of not using the adjustability that tuners give. With index marks, it's simple enough to put the tuner right back where it was or to adjust for tune. Again, IME, adjustments are very small but clear on the target. Worrying about getting lost is not an issue.

Of course Gene is also one of the best ever at keeping up with tune by the traditional powder charge/seating depth method. That would surely be a factor in why he uses a tuner as simply a weight.

mwezell
02-28-2015, 01:04 PM
Changing Genes and going to Gene Beggs.
We have been using the Gene Beggs tuners ever since I quit bashing them and actually tried them. We tune as dictated to by the Kestrel 4000 Weather Tracker and the Density Altitude that it calculates. My range notes are in a safe right now and I don't feel like standing up, walking across the room, and unlocking the safe but I'd say we've used the Beggs Tuners for about 8 years. What was appealing to us is that they weigh 4 ounces and in LV class you don't have a lot of weight to give away with some stock, action, barrels. For one inch of the barrel you have to take the O.D. down to a diameter and thread it for the tuner so the tuner installation doesn't actually add 4 ounces to the rifle. We have scribed the tuners with marks representing one hour around the tuner. A change of 250 feet of density altitude dictates a turn of one hour (1/12th rotation) on the tuner in our case(s). I use the plural because we have a tuner on about 8 or 10 barrels and they all react differently. Before I went the route of the tuner, Calfee was an idiot and Gene Beggs didn't know what he was talking about. But then we started actually using the tuner and had to admit that Calfee and Beggs were right.
So Scott, what are you doing these days? You can e-mail me at my e-mail by clicking my name. Did I hear you are no longer at UPS?

That sounds about right Francis. With the difference in weight between the Beggs tuner and mine, both being 32 tpi, mine extending beyond the muzzle..yada, yada..

I recently was able to closely calculate the weight needed for one of my tuners to respond with similar tuner movements as I typically see on hv contour barrels, but on a 1.450 barrel blocked rifle with 19" of barrel beyond the block. When all was said and done, total tuner weight was 15.9ozs and the barrel responded to tuner movement very much the same as a 7.4 ounce tuner on my hv rig. Point being, this is all quite predictable. I used Dan Lilja's barrel stiffness calculator to figure how much the tuner should weigh to get it to act like mine. It seemed to work out very close to what I'd hoped for. That rifle was a 57lb 30BR in an aluminum Baer stock. It's all noise at that weight. It'll be shot in UBR unlimited class.

scott mims
02-28-2015, 01:17 PM
this post went better than i thought it would. i was waiting to be laughed at. so i guess all of that has been done? thanks for all the replies. Frances i sent you a private message. hope yall are doing good.

Dusty Stevens
02-28-2015, 02:50 PM
Id love to have a baer aluminum hg stock

mwezell
02-28-2015, 03:54 PM
Id love to have a baer aluminum hg stock

Me too Dusty. He's suppose to send me some better pics soon. This is all I have of it finished. It makes a NF BR look small, so it's a big un'.
http://i196.photobucket.com/albums/aa297/mwezell/ron%20jackson%20hg_zpsq8b5w1ix.jpg

Greyfox
02-28-2015, 05:11 PM
Mr Jackson is going to be tough to beat. The competition may be for 2nd place. OTOH- maybe I'll just have to go to more matches that he doesn't shoot ;)

Rick

jackie schmidt
02-28-2015, 06:50 PM
On barrels found in 100-200 yard Benchrest, the weight of the tuner is of no consequence. Mine go about 4 ounces.

The best tuners, (IMHO), are the ones with some type of dampener, or as some say, a snubber. I like to believe that this is my creation, if you look back in the archives of Benchrest.com, you might agree. But regardless who came up with it, it works.

Also, how much you turn the tuner depends on the Threads Per Inch of the adjustment. Mine are 36 TPI. 1/4 turn is a pretty fine adjustment.

Here is the snubber tuner on my LV.

http://benchrest.com/attachment.php?attachmentid=15918&stc=1&d=1425167415

jackie schmidt
02-28-2015, 06:52 PM
Front view.

http://benchrest.com/attachment.php?attachmentid=15918&stc=1&d=1425167415

mwezell
02-28-2015, 06:59 PM
Mr Jackson is going to be tough to beat. The competition may be for 2nd place. OTOH- maybe I'll just have to go to more matches that he doesn't shoot ;)

Rick
From what I saw from this rifle, and knowing how well Ron can shoot...you might be right. I think the rifle is possibly the ideal unlimited rifle for benchrest for score.

Dusty Stevens
02-28-2015, 07:17 PM
Ive got one exactly like it- same shape and all but its made of fiberglass and lead shot. Its 60+ lbs bare stock

mwezell
02-28-2015, 07:34 PM
Wow! How bad do you want an aluminum stock like it?

scott mims
02-28-2015, 08:30 PM
i know this has been asked and answered before but what i have always wanted to know is......... with our 6ppc most loads are between 52.5 and 55 clicks. do people with tuners go with the average (53.75) or around there...... load all their loads with that and just adjust the tuner until they find the tune without adding powder or loading less powder? or do people still change loads along with the tuner? is the tuner strictly for small adjustments? i have a hard time with just trying to go up or down on powder i couldnt imagine adding another variable.

Also in my first post when I was saying rubber washer I meant a rubber O ring

Dusty Stevens
02-28-2015, 08:35 PM
Id like to have one but i dont want to get out of control and sell a corvette or anything like that

John Kielly
02-28-2015, 10:08 PM
Over here, I shoot in a belly sport (we call it Match Rifle) over 1000, 1100 & 1200 yards using the standard .308 Winchester case - with long throats for the 190-215 grain projectiles we use. See us here: http://www.matchrifle.org/

To get those buggers to 1200 yards comfortably, you need to squeak the most velocity possible out of them, then tweak them for accuracy. The way a lot of us do it is load test molied bullets jumping around .025" over a chronograph until we get 15 shot spreads at least under 15 fps, then tweak them with a behind the muzzle tuner weighing around 2 ounces. We've found that within bounds the lighter the mass of the tuner we use, the more forgiving is the tune that we achieve, albeit it might be a tad less accurate than if we'd tuned for a single distance with bigger tuners. Set it up right for one distance & it will work OK for the rest.

Oh, yes, we're loading to the milligram with out powder charges, not the click.

JerrySharrett
03-01-2015, 05:49 AM
Being undisputedly the FIRST 100/200centerfire shooter to shoot ALL the major events, in a single year, Super Shoot, both nationals, the Shamrock, Hog Roast, and 4 local shoots using a tuner, even before they were "approved" by the IBS I'll make a comment or two. The year was 2005.

You can take a light weight tuner, say in the under 5 ounce range, you can tune for the moment. I.E. within a given setup, conditions, powder ,bullet, etc., you can use a light weight tuner and change how the gun is shooting....for the moment. You will notice with current tuner users they keep adjusting during the day. Using this method and tuner type, the tuner becomes another choice of something to use during the shoot.

If your intention is to use a tuner to get maximum accuracy OUT OF A BARREL, the tuner must weigh over the 5 ounce range in its construction. I never went far enough to determine the break-over point but the tuners Scott "Fudd" Hamilton, of Fudd Tuner fame, made for me in January 2005, the tuner needs to be about 10 ounces or more. In having a tuner that heavy and shooting in our LV class the weight of the barrel must be reduced. If you will search for some old posts of mine dating from after 2005 you will find pictures I posted of about 6-8 different configurations from just straight turning, like the rimfire guys do, to "exotic" shapes like the Mauser steps that Mauser used in his early models.

Bottom line, to get the maximum capable accuracy out of a given barrel the tuner needs to be heavy. To simply to add another tuning tool the tuner can be light.

Or you can do like George Kelbly Sr and Paul Gottshal did many years ago. They took a bronze bearing sleeve that weighed about 5 pounds and simply clamped it to the barrel with setscrews. George's comment was "all it did was lower the impact point". George still has that "tuner" somewhere at their shop.

.

dickw
03-01-2015, 06:40 AM
would be holding them in exactly the same place on the barrel.

mwezell
03-01-2015, 07:13 AM
Being undisputedly the FIRST 100/200centerfire shooter to shoot ALL the major events, in a single year, Super Shoot, both nationals, the Shamrock, Hog Roast, and 4 local shoots using a tuner, even before they were "approved" by the IBS I'll make a comment or two. The year was 2005.

You can take a light weight tuner, say in the under 5 ounce range, you can tune for the moment. I.E. within a given setup, conditions, powder ,bullet, etc., you can use a light weight tuner and change how the gun is shooting....for the moment. You will notice with current tuner users they keep adjusting during the day. Using this method and tuner type, the tuner becomes another choice of something to use during the shoot.

If your intention is to use a tuner to get maximum accuracy OUT OF A BARREL, the tuner must weigh over the 5 ounce range in its construction. I never went far enough to determine the break-over point but the tuners Scott "Fudd" Hamilton, of Fudd Tuner fame, made for me in January 2005, the tuner needs to be about 10 ounces or more. In having a tuner that heavy and shooting in our LV class the weight of the barrel must be reduced. If you will search for some old posts of mine dating from after 2005 you will find pictures I posted of about 6-8 different configurations from just straight turning, like the rimfire guys do, to "exotic" shapes like the Mauser steps that Mauser used in his early models.

Bottom line, to get the maximum capable accuracy out of a given barrel the tuner needs to be heavy. To simply to add another tuning tool the tuner can be light.

Or you can do like George Kelbly Sr and Paul Gottshal did many years ago. They took a bronze bearing sleeve that weighed about 5 pounds and simply clamped it to the barrel with setscrews. George's comment was "all it did was lower the impact point". George still has that "tuner" somewhere at their shop.

.

Thanks Jerry, that pretty well mirrors what I've found.
The thing about light tuners is that they can't increase the amplitude as much as a heavier tuner. Amplitude is what effectively slows the muzzle and creates longer dwell time at nodes. It also makes tuning more apparent on target. In practice, and as Jerry said, lighter tuners(to a point) can give adjustability but don't broaden the node as much as heavier designs.

If lightening a barrel means shortening existing contours, the barrel gains stiffness rapidly, therefore needing more tuner weight to give the same effect....sort of a catch 22. This is why Boyd and I have been discussing hinging the barrel. The idea is to reduce the barrel od for a section a few inches after the receiver face, to the point where muzzle deflection is the same or more than it would be prior to cutting it down. The theory is that it would tune much the same as it did before cutting and without needing more tuner weight to do it.

As for tuners adding another variable, I see it just the opposite. To me, it's much easier to learn how to use a tuner than to learn to keep a gun in tune with powder charge/seating depth. If one is determined to tune the traditional way and leave the tuner set, then he still sees the broader tune benefit with no other variables.

mwezell
03-01-2015, 07:25 AM
i know this has been asked and answered before but what i have always wanted to know is......... with our 6ppc most loads are between 52.5 and 55 clicks. do people with tuners go with the average (53.75) or around there...... load all their loads with that and just adjust the tuner until they find the tune without adding powder or loading less powder? or do people still change loads along with the tuner? is the tuner strictly for small adjustments? i have a hard time with just trying to go up or down on powder i couldnt imagine adding another variable.

Also in my first post when I was saying rubber washer I meant a rubber O ring

Scott, herein lies the beauty of a tuner. Given your example and assuming that 55 clicks is at or near max in your gun, I'd load the 52.5 click load and adjust the tuner to it. No need to shoot a load that could be too hot on some days, but the load has to be a good one in your rifle. Tuners won't fix bad loads. Where that's confusing is that your bad load might be a good one at a certain temp or condition. For purposes here, lets just say to go with your known good lower end load and not have to deal with high pressures..anymore. You could just as easily go with the 53.75 load, as long as it's a proven load in your gun. I'd just stay away from the potential brass wrecker loads. With a tuner, there's no reason to go there in short range.

mks
03-01-2015, 09:45 AM
Amplitude is what effectively slows the muzzle and creates longer dwell time at nodes.

Mike,
I think this needs some explanation, because it is at odds with the conventional terminology of vibration analysis. First, amplitude means the peak-to-peak displacement or angle change of the vibration wave. For a given frequency, greater amplitude means that speed must increase. (Like moving point B farther from point A, to get from A to B in the same time, we have to go faster.)

Second, there is no dwell time for a muzzle. It is in constant motion. In fact, we want it to move. If we could get it to "stop," then it would not be tuned because there would be no positive compensation. What we want to happen is that the muzzle angle is rising at the perfect speed (not too fast and not too slow) such that slow bullets, which leave the muzzle later, are launched at a higher trajectory such that they hit the target at the same point as the fast ones.

Lastly, a node is normally defined as a point along a vibration waveform that doesn't oscillate in position. For a steady wave, the locations of the nodes don't change. Halfway between the nodes are the antinodes, where maximum displacement occurs.

Seems like you may be using these terms differently.

Cheers,
Keith

JerrySharrett
03-01-2015, 10:56 AM
Thanks Jerry, that pretty well mirrors what I've found.

As for tuners adding another variable, I see it just the opposite. To me, it's much easier to learn how to use a tuner than to learn to keep a gun in tune with powder charge/seating depth. If one is determined to tune the traditional way and leave the tuner set, then he still sees the broader tune benefit with no other variables.

It appears to me many of the light tuner users are adjusting at the bench after the load is loaded. During sightin is when I see them doing most of the adjusting. The tuner is another variable or option if you want to call it that. Its up to the shooter as which they wish to tune with. Any way you look at it, the tuner adds another choice.

With a heavy tuner the shooter can tune the barrel to its optimum, then continue as previous with a barrel that is in better natural tune.

Chicken or egg, or egg and chicken.

Boyd Allen
03-01-2015, 11:47 AM
I was able to compensate for the entire weight of a 5 1/4 oz. tuner by stepping the barrel, this without reducing the muzzle diameter, or shortening the barrel. I ran the cylindrical sections back (about 6 1/2 inches) till the step up to the original contour was about .100 in diameter, and then cut another at that diameter to the point where the step up was the same (for a total of two steps). I had calculated this before we did it, and it came out as planned. Accuracy and the tune window seemed to have been increased. The weight added at the muzzle was one of Jackie's early tuners plus a Deresonator. Because I had fitted the tuner to the barrel such a short time before the match, I lacked the data to make tuner adjustments during the match, so I went with my original setup as far as tuner setting, and made one powder adjustment through the days to compensate for increasing temperature. Tune seemed much less fussy, and the gun seemed to shoot closer to what the flags were showing than it had before. To me, there does not seem to be much of a barrier to using tuners over five ounces on a 10 1/2# rifle. I could have cut another cylindrical section/step on the barrel and taken off even more weight. We took a lot of very light cuts when stepping the barrel. It was button rifled.

mwezell
03-01-2015, 12:23 PM
Mike,
I think this needs some explanation, because it is at odds with the conventional terminology of vibration analysis. First, amplitude means the peak-to-peak displacement or angle change of the vibration wave. For a given frequency, greater amplitude means that speed must increase. (Like moving point B farther from point A, to get from A to B in the same time, we have to go faster.)

Second, there is no dwell time for a muzzle. It is in constant motion. In fact, we want it to move. If we could get it to "stop," then it would not be tuned because there would be no positive compensation. What we want to happen is that the muzzle angle is rising at the perfect speed (not too fast and not too slow) such that slow bullets, which leave the muzzle later, are launched at a higher trajectory such that they hit the target at the same point as the fast ones.

Lastly, a node is normally defined as a point along a vibration waveform that doesn't oscillate in position. For a steady wave, the locations of the nodes don't change. Halfway between the nodes are the antinodes, where maximum displacement occurs.

Seems like you may be using these terms differently.

Cheers,
Keith

Hi Keith! I look forward to seeing you at a match soon.

First, technically you're correct, as usual. I was trying to keep things as simple as possible. The majority of us get confused when we start talking about amplitude and frequency. When all is said and done, how tuners work is far less important to most of us than how we can make them work for us.

For what I consider the purposes of this conversation, I think thie following definition of amplitude will suffice.

...the maximum extent of a vibration or oscillation, measured from the position of equilibrium.

This implies a couple of things. First of all, while the muzzle technically never stops moving, it does have a maximum amount of displacement, both vertically and horizontally. The mass(tuner) at the end of the barrel, along with gravity make it's movement vertically biased. A heavier tuner does this moreso than a lighter one...again, gravity here. In layman's terms, amplitude can be considered how far the muzzle moves, in this context, vertically. But due to the fact that it oscillates, I think somewhat skinny eggshaped would be a decent description of the muzzle displacement as it oscillates, vertically biased.

When I used the term dwell time, I do so because we have a point at top and bottom where the muzzle slows and changes direction. This is where I hope bullet exit occurs, not while the barrel is at full song going in either the up or downward(biased) part of its swing. IOW, we have a point at top and bottom of LESS movement for a period. This is what I referred to as dwell time, be it technically correct or not. The area just before maximum vertical displacement is the area that I try to tune to...for positive compensation and because of it being near the top of it's oscillation, where movement is slowed before it changes direction, and starts back down.

Adjusting the tuner changes the frequency of the vibration. Again, I think this definition of frequency applies here.

...the number of cycles or completed alternations per unit time of a wave or oscillation. Symbol: F;

IOW, how far between nodes.

FWIW, I have had someone you may know at the University of Cincinnati do some viration analysis testing with my tuners. His name is Sam Glover. I hope we can conclude the testing soon. I don't think anyone fully understands everything that's going on with tuners yet, but Sam is very qualified and his son is working with him on this. He's a mechanical engineer, specializing in vibration analysis. Sam is a shooter, so he has a good understanding of what we're looking for. He's also a nuclear physicist and former adviser at Los Alamos National Laboratory.

One thing that has been proven is a 35% lowering of the frequency of the test barrel with my tuner vs, no tuner. What this tells us is that we have greater amplitude, as mentioned earlier, and a lower frequency of vibration. So, we have slowed the muzzle displacement by lowering the frequency and lengthened the period where the barrel is moving slowest in its oscillation with more amplitude. We have yet to discuss how the dampening agent in my tuners affects this, too.

Here's a good read of my basis for using particle dampening, in a research done at Texas A&M. I very highly recommend everyone read it. It's quite interesting and is why I feel like my tuners are the next step in tuner design.
http://repository.tamu.edu/bitstream/handle/1969.1/1459/etd-tamu-2003C-AERO-Marhadi-1.pdf?sequence=1

You are also correct in pointing out my misuse of the term "node". Keep in mind, I was trying to relay what I'm saying in terms that "most" of us understand...myself included.

I certainly understand you pointing out what you have, Keith. But part of the trouble with tuners is the confusion and speaking over most of our heads when it comes to describing what they do. I read your posts with interest, as I have everything I could find on the subject since 2006 or 2007, when I started playing with tuners. I'm 100% convinced that I won't be shooting without a tuner until something better comes along.--Mike

Boyd Allen
03-01-2015, 01:12 PM
Changing the subject a bit. Has anyone observed that moving a given amount of mass farther in front of the muzzle creates more effect? Related to this, when one has a tube in front of the crown, is there an ID to length ratio that needs to be taken into account? The obvious point of my question is that perhaps we can reduce the total weight of a tuner, by moving the weight farther in front of the muzzle. One other issue that may come up with this is that the integrity of the tuner barrel joint may be more critical.

mwezell
03-01-2015, 01:25 PM
Changing the subject a bit. Has anyone observed that moving a given amount of mass farther in front of the muzzle creates more effect? Related to this, when one has a tube in front of the crown, is there an ID to length ratio that needs to be taken into account? The obvious point of my question is that perhaps we can reduce the total weight of a tuner, by moving the weight farther in front of the muzzle. One other issue that may come up with this is that the integrity of the tuner barrel joint may be more critical.

Boyd, I love how you're always thinking! Obviously, if the attachment is good and the tube very rigid, the difference would be simple leverage. Somehow I believe you're thinking beyond that. If the tube had some flexibility, would that be bad?:confused:Hmmm.

TSI243
03-01-2015, 01:54 PM
Boyd
I did a lot of experimenting with tuners when I was developing my Tuner/Snubber including playing with overhang, as you know my Tuner dose overhang the muzzle by about an 1" .

What I found was:

Overhang is a good thing and dose increase the effectiveness of the tuner

As overhang increases there is a point where gasses, exiting the bore behind the bullet, going faster than the bullet, exit the muzzle, expand out, hit the tuner ID, and rebound back into the tuner ID. If these gases, which are quite turbulent by this time, do impact the bullet before it leaves the tuners bore, it's not a happy condition -- bad things happened to the bullet ---ask me how I know ???

I did find that unhappy point of overhang. My tuner is safely short of that point. Using my tuners you can be assured that the bullet is long gone by the time gasses are rebounding back to the ID.

When developing my tuners I also played with methods of attaching the tuner to the barrel and I can assure you that the tuner must have solid contact to the barrel and can not move during firing. When I adjust my tuner I move it in 1/8 of a turn increments on a 32 pitch thread -- that is a movement of only .004 --and I can assure you that this can be seen on paper, and that little bit of movement dose make a diference. Tuner lock up with the barrel must be solid!!! I can't stress this enough!!

Gene Bukys

jackie schmidt
03-01-2015, 02:55 PM
+1000 on what Gene says.

mks
03-01-2015, 03:29 PM
Mike,
It has been a while since we have been at the same match. I hope to shoot more this summer, and to see you and your new tuner in person.

If there is one misconception about tuners that I would like to clear up more than any other…well, actually there are two that are related.

First is that the barrel should be moving slowly to be tuned. This is false. It needs to be moving rapidly for positive compensation. Probably more rapidly than most BR rifles are capable, without a muzzle mass.

Second, that the muzzle position, high or low, is important. This also is false. It is muzzle angle that is paramount.

For example, take a fishing rod and point it horizontally. Then rotate the grip quickly upward, as if to make a back cast with only your wrist, and no arm motion. This simulates the rotation that recoil causes in a rifle. The rod tip rises, but as it does so, it still points downward. Likewise, when the muzzle of a rifle reaches it highest point, it is still pointed low on the target.

Now, rotate the grip back down in time with the rod's natural tendency to whip back and forth. The tip continues to rise, even though the rest of the rod is accelerating downward. Notice that the tip is pointed highest some time later as it is traveling downward. So for the rifle barrel, the time we want bullets to exit is when the muzzle angle is rising, and we shouldn't care whether muzzle position is high or low or in the middle. Typical, stiff rifles need bullet exit timed to be near the time of maximum rate of muzzle angle change (angular velocity), which tends to be when the rest of the barrel is traveling downward the fastest.


Cheers,
Keith

Gene Beggs
03-01-2015, 04:49 PM
Yes sir, Scott! Your tuner thread has brought out some terrific discussion among the most knowledgeable shooters in the world. :cool:

Anything said about barrel tuners and barrel vibration always commands my undivided attention. There have been some very good points made here. Lots of smart individuals, some with impressive degrees and qualifications have experimented with tuners at length during the past ten years or so. Great progress has been made but I'm sure there will be new discoveries and improvements made in the future.

Later,

Gene Beggs

mwezell
03-01-2015, 05:26 PM
Boyd
I did a lot of experimenting with tuners when I was developing my Tuner/Snubber including playing with overhang, as you know my Tuner dose overhang the muzzle by about an 1" .

What I found was:

Overhang is a good thing and dose increase the effectiveness of the tuner

As overhang increases there is a point where gasses, exiting the bore behind the bullet, going faster than the bullet, exit the muzzle, expand out, hit the tuner ID, and rebound back into the tuner ID. If these gases, which are quite turbulent by this time, do impact the bullet before it leaves the tuners bore, it's not a happy condition -- bad things happened to the bullet ---ask me how I know ???

I did find that unhappy point of overhang. My tuner is safely short of that point. Using my tuners you can be assured that the bullet is long gone by the time gasses are rebounding back to the ID.

When developing my tuners I also played with methods of attaching the tuner to the barrel and I can assure you that the tuner must have solid contact to the barrel and can not move during firing. When I adjust my tuner I move it in 1/8 of a turn increments on a 32 pitch thread -- that is a movement of only .004 --and I can assure you that this can be seen on paper, and that little bit of movement dose make a diference. Tuner lock up with the barrel must be solid!!! I can't stress this enough!!

Gene Bukys

Hi Gene,
I don't disagree with any of what you say except relative to the solid mounting. If sensitive enough vibration analysis equipment is used you'll find that short of welding a tuner on, there is still going to be slight movement at the joint. Obviously, the tuner must not be free to move all over the place. A few of us have seen what happens when a tuner gets loose, and you're right...it's not good. But clamping with pinch bolts is only a partial fix for the small movement I referred to earlier. We may think it's solid, but it's not. Nor would it be if it were pressed on with considerable interference fit. Ever cut a pressed on bearing race from a shaft with a torch? It's relatively easy to do without hurting the shaft it's pressed on to. Same principle...It's not one piece as it would be if it were welded so the heat doesn't transfer to the shaft the same way. Same goes for vibration between two parts...they're not one part with pinch bolts.

The good news is that if addressed in a way such as yours, with pinch bolts, that small amount of movement at the joint does appear to be a non-factor, or at least not one that stands outside of the noise.--Mike

mwezell
03-01-2015, 05:32 PM
Yes sir, Scott! Your tuner thread has brought out some terrific discussion among the most knowledgeable shooters in the world. :cool:

Anything said about barrel tuners and barrel vibration always commands my undivided attention. There have been some very good points made here. Lots of smart individuals, some with impressive degrees and qualifications have experimented with tuners at length during the past ten years or so. Great progress has been made but I'm sure there will be new discoveries and improvements made in the future.

Most of the centerfire work with tuners has been done by group shooters at 100 and 200 yds where one can easily see the bullet holes and make tuner adjustments as necessary. You can't see your bullet holes at longer ranges so I don't know how you could ever make meaningful adjustments. I think time will show that barrel tuners are useful only to short range extreme accuracy shooters. Long range, hunting and tactical shooting? Forget it! :o

Later,

Gene Beggs

Hi Gene,
I disagree, but only with the long range part. Even if a tuner is never moved, it still has benefits. So, if one can be successful tuning w/o a tuner at long range, they can also be successful with a tuner, but enjoy the wider tune window they offer.--Mike

TSI243
03-01-2015, 05:41 PM
It's a rainy day here in Houston ---

Gene Beggs my friend, i would like to disagree with your feeling that tuners are only useful on centerfire rifles used for short range bench rest.

I think that it was Browning that brought out their combination muzzle Break/ Tuner on their hunting guns -I don't remember what they call it ?? but it's available on Winchester rifles now as well. I know that Winchester and Browning are the same company now and that's why it's available on the Winchester rifles?? -- I think that their system is not offered by others because Browning patented the system.

I think that tuners are just now starting to make their entrance onto the long range scene as well -- Nick Marino is using one and doing quite well with it at his 600 yard F-class shoots.

I don't shoot long range that much but I do have one on my long range rifle -- A 300 WSM, and I find it to be quite effective.

In reality, Tuners are not all that prevalent yet even in short range benchrest -- It seems to me that if you look around at Nationals or the SS that less than 25% of the shooters are using them ?? perhaps less ??? I think that the only place that tuners are the norm is in the rimfire area ??

I think that time will show that tuners will continue to make inroads into short range benchrest, and that we will see more and more being used on long range rifles.

Hunting rifles ?? I don't know tuners may not make such a big splash there ??? perhaps because ultimate accuracy is not a requirement there ??

Gene Bukys

mwezell
03-01-2015, 05:48 PM
Mike,
It has been a while since we have been at the same match. I hope to shoot more this summer, and to see you and your new tuner in person.

If there is one misconception about tuners that I would like to clear up more than any other…well, actually there are two that are related.

First is that the barrel should be moving slowly to be tuned. This is false. It needs to be moving rapidly for positive compensation. Probably more rapidly than most BR rifles are capable, without a muzzle mass.

Second, that the muzzle position, high or low, is important. This also is false. It is muzzle angle that is paramount.

For example, take a fishing rod and point it horizontally. Then rotate the grip quickly upward, as if to make a back cast with only your wrist, and no arm motion. This simulates the rotation that recoil causes in a rifle. The rod tip rises, but as it does so, it still points downward. Likewise, when the muzzle of a rifle reaches it highest point, it is still pointed low on the target.

Now, rotate the grip back down in time with the rod's natural tendency to whip back and forth. The tip continues to rise, even though the rest of the rod is accelerating downward. Notice that the tip is pointed highest some time later as it is traveling downward. So for the rifle barrel, the time we want bullets to exit is when the muzzle angle is rising, and we shouldn't care whether muzzle position is high or low or in the middle. Typical, stiff rifles need bullet exit timed to be near the time of maximum rate of muzzle angle change (angular velocity), which tends to be when the rest of the barrel is traveling downward the fastest.


Cheers,
Keith
Keith, again, unless I'm reading something wrong, we're still saying pretty much the same thing. I think you're referring to what's happening more behind the muzzle, that affects the angle, where I'm saying at the muzzle. I don't know if we agree about the barrel needing to be moving fast for positive compensation, but I'll take your word for it and I see what you're saying. Wouldn't a short stiff barrel move faster?

Nevertheless, results are what matter most. I'm completely satisfied with those. I am thankful we have people like you in this game that want to understand why and how tuners do what they do and are qualified to help figure that out.

My tuner is the result of utilizing proven designs along with a few features that separate it from them, but I think we can agree that whatever makes two washers tightened together near the muzzle work, also applies to mine.:)

Gene Beggs
03-01-2015, 05:52 PM
Hi Gene,
I disagree, but only with the long range part. Even if a tuner is never moved, it still has benefits. So, if one can be successful tuning w/o a tuner at long range, they can also be successful with a tuner, but enjoy the wider tune window they offer.--Mike



,,,,,,talking about things I know nothing about. :rolleyes: In this case, long range shooting. :p :o

I've been guilty before of making comments about things that are out of my area of expertise. I'll be more careful.

By the way, I would like to take this opportunity to say how impressed I've been with your knowledge, products, and the way you share your experience with others. You know what you're talking about! :D

Best of luck to you with all your ventures. Keep up the good work and stay in touch.

Later,

Gene Beggs

mwezell
03-01-2015, 05:59 PM
It's a rainy day here in Houston ---

Gene Beggs my friend, i would like to disagree with your feeling that tuners are only useful on centerfire rifles used for short range bench rest.

I think that it was Browning that brought out their combination muzzle Break/ Tuner on their hunting guns -I don't remember what they call it ?? but it's available on Winchester rifles now as well. I know that Winchester and Browning are the same company now and that's why it's available on the Winchester rifles?? -- I think that their system is not offered by others because Browning patented the system.

I think that tuners are just now starting to make their entrance onto the long range scene as well -- Nick Marino is using one and doing quite well with it at his 600 yard F-class shoots.

I don't shoot long range that much but I do have one on my long range rifle -- A 300 WSM, and I find it to be quite effective.

In reality, Tuners are not all that prevalent yet even in short range benchrest -- It seems to me that if you look around at Nationals or the SS that less than 25% of the shooters are using them ?? perhaps less ??? I think that the only place that tuners are the norm is in the rimfire area ??

I think that time will show that tuners will continue to make inroads into short range benchrest, and that we will see more and more being used on long range rifles.

Hunting rifles ?? I don't know tuners may not make such a big splash there ??? perhaps because ultimate accuracy is not a requirement there ??

Gene Bukys

Gene, I'd say roughly half or a little more score shooters where I shoot use some type of tuner. Of course the 13.5lb weight limit makes any tuner easier to utilize without gun balance problems. I do agree that they are becoming more prevelant all the time. --M

TSI243
03-01-2015, 06:02 PM
Seems this is my day to be disagreeable

Mike;
Im gonna have to disagree with you as well -- It is quite possible to put parts together with bolts or interference fits and they do in fact become one -- with no, None, Nada, movement between components, not the slightest bit of movement!!!
The bearing fit that you referred to came loose because you heated the race and it expanded and turned loose. but while it was shrunk onto the shaft there was no movement between the race and shaft it was sitting on if it in fact had an interference fit!!

I work with shrink fits all the time and if done properly the parts do in fact become one -- so will a bolted joint

Now having said all that I don't know if my pinch bolt on my tuners is that tight ?? it might actually move some at some microscopic level. But I don't think so !! it is a solid joint and will not ever change unless I loosen the pinch bolt.

Gene Bukys

mwezell
03-01-2015, 06:08 PM
,,,,,,talking about things I know nothing about. :rolleyes: In this case, long range shooting. :p :o

I've been guilty before of making comments about things that are out of my area of expertise. I'll be more careful.

By the way, I would like to take this opportunity to say how impressed I've been with your knowledge, products, and the way you share your experience with others. You know what you're talking about! :D

Best of luck to you with all your ventures. Keep up the good work and stay in touch.

Later,

Gene Beggs
Thank you very much Gene! Keith is more qualified but I listen, read, and try to learn about things that interest me....and I put my money where my mouth is. I don't mind trying new things. I have been consciously trying not to speak unless it's something I feel like I have tested and at least proven to my own satisfaction, to be worthy of talking about.

Problem is, I'm more of a ky hillbilly than an engineer, so I should probably be quiet more often. :o

TSI243
03-01-2015, 06:09 PM
Mike
finally I agree ---

I think that if you were to walk onto the Tomball rifle range during a registered shoot you might well find that about half or even more of the competitors are in fact using tuners of some type -- so it's kinda regional
if a shooter is in an area where tuners are in wide use he will most likely go with a tuner --

I wonder if the score nationals had the same percentage of tuner usage ??

Gene

mwezell
03-01-2015, 06:11 PM
Seems this is my day to be disagreeable

Mike;
Im gonna have to disagree with you as well -- It is quite possible to put parts together with bolts or interference fits and they do in fact become one -- with no, None, Nada, movement between components, not the slightest bit of movement!!!
The bearing fit that you referred to came loose because you heated the race and it expanded and turned loose. but while it was shrunk onto the shaft there was no movement between the race and shaft it was sitting on if it in fact had an interference fit!!

I work with shrink fits all the time and if done properly the parts do in fact become one -- so will a bolted joint

Now having said all that I don't know if my pinch bolt on my tuners is that tight ?? it might actually move some at some microscopic level. But I don't think so !! it is a solid joint and will not ever change unless I loosen the pinch bolt.

Gene Bukys
Gene, we can agree to disagree about something that doesn't seem to matter, but science is on my side in this one.;)

mwezell
03-01-2015, 06:13 PM
Mike
finally I agree ---

I think that if you were to walk onto the Tomball rifle range during a registered shoot you might well find that about half or even more of the competitors are in fact using tuners of some type -- so it's kinda regional
if a shooter is in an area where tuners are in wide use he will most likely go with a tuner --

I wonder if the score nationals had the same percentage of tuner usage ??

Gene
I would say yes at the UBR Nationals, but I wasn't at either the IBS or NBRSA Score Nats. UBR itself is still pretty regional though.

BTW, your tuner is the one that got my wheels turning, and ultimately led to mine.

mwezell
03-01-2015, 07:15 PM
FWIW, here's a pic of my centerfire tuner on my HV rifle. There are 9 pockets unde the cover that contain tungsten powder. This is the particle dampening. There's a link above in one of my posts about it's benefits done at Texas A&M.
Again, Gene Bukys' tuner is what got me headed down this path of using something other than a hunk of metal for dampening.

Even if all else was equal between it and other tuners, it looks nicer than most.
Most importantly, they work! If you can stand the weight on your rifle, I highly recommend everyone to at least try SOMEONE'S tuner.
Shiraz stocks my centerfire tuners and Dan Killough stocks my rimfire version of it.

-Adjusted as it is, the muzzle is pretty much flush with the step below the engraving.--Mike


https://fbcdn-sphotos-c-a.akamaihd.net/hphotos-ak-xpf1/v/t1.0-9/10996651_10204824672631259_135349867095665734_n.jp g?oh=d51f11b56537d71233b56c2a0b4c3ec4&oe=55755733&__gda__=1434886924_912cec8473963f0541b1fb80d1c729c c

SCOTTY CRAWFORD
03-01-2015, 08:36 PM
Mike,
Where is the pic of the tuner with the tuner cover installed??? Inside joke you had to be there!

TSI243
03-01-2015, 08:43 PM
"Gene, we can agree to disagree about something that doesn't seem to matter, but science is on my side in this one."

No Science is not on your side on this one ?? if you think it is please explain the science ??

Fact is if I simply set one part on the top of another and applied no force to either part, the parts would have no movement between them -- none !! they would sit there forever with nothing but gravity holding them together!!

so it's a matter of the forces applied to the parts -- if the interference fit, or bolting, or whatever means we use to attache one part to another, rubber bands, gravity or whatever, produces a force holding the parts together that is greater than the force that is applied to the parts to separate them, there will be no movement between the parts, none at all !!!

even if you weld them together if the force applied to the parts is greater than the strength of the weld, the weld will fail !!

so it's all about the force holding parts together and the force that is trying to separate them --

and don't confuse heat transfer between parts with movement!! heat transfer is a whole new topic -- and not relevant to anything here


Gene Bukys

jackie schmidt
03-01-2015, 09:28 PM
Well, we certainly don't want to let actual results in competition at every level of Benchrest, including region championships, national championships, and world championships, get in the way of a good theory.

Gene, I think you need to abandon all of your match proven ideas and start all over, especially before this years Crawfish.:D

mwezell
03-01-2015, 10:48 PM
"Gene, we can agree to disagree about something that doesn't seem to matter, but science is on my side in this one."

No Science is not on your side on this one ?? if you think it is please explain the science ??

Fact is if I simply set one part on the top of another and applied no force to either part, the parts would have no movement between them -- none !! they would sit there forever with nothing but gravity holding them together!!

so it's a matter of the forces applied to the parts -- if the interference fit, or bolting, or whatever means we use to attache one part to another, rubber bands, gravity or whatever, produces a force holding the parts together that is greater than the force that is applied to the parts to separate them, there will be no movement between the parts, none at all !!!

even if you weld them together if the force applied to the parts is greater than the strength of the weld, the weld will fail !!

so it's all about the force holding parts together and the force that is trying to separate them --

and don't confuse heat transfer between parts with movement!! heat transfer is a whole new topic -- and not relevant to anything here


Gene Bukys

Gene, I'll find a link sooner or later, but as I said earlier, I think it's irrelevant, or gets lost in the noise either way, so there's not much point in debating it. If two washers can be hand tightened against one another in a tuner design that works, I'd say what we're talking about is quite irrelevant.

mwezell
03-01-2015, 10:54 PM
Well, we certainly don't want to let actual results in competition at every level of Benchrest, including region championships, national championships, and world championships, get in the way of a good theory.

Gene, I think you need to abandon all of your match proven ideas and start all over, especially before this years Crawfish.:D

Jackie, thanks so much for your thoughtful contribution in that post. We're all very grateful and could tell you put a lot of effort into it.:rolleyes:

jackie schmidt
03-02-2015, 12:23 AM
Jackie, thanks so much for your thoughtful contribution in that post. We're all very grateful and could tell you put a lot of effort into it.:rolleyes:

Your welcome. Sarcasm noted.

JerrySharrett
03-02-2015, 05:35 AM
On the subject of how to mount a tuner there are generally two methods used, screw on and clamp on. The Fudd tuners I was using, being clamp-on design, if I clamped them on would simply slide off over time since these tuners were of the ahead-of-the-muzzle design. If I clamped the tuner on using over about 65 in/lb, then slugged the bore I could easily feel the bore being choked down. I solved that problem by leaving the last 1/32" or so about 0.005" larger than the diameter where the tuner was to fit.

On the method of screwing the weight(s) on, consideration needs to be given to how that fit-up takes place and how the screw-on weights are configured. In 2005 for the IBS tuner, being that the IBS had not disallowed tuners but required any additional barrel weight to not extend beyond the maximum diameter profile of a HV barrel. (This "unofficial ruling" came from the IBS group committee, namely Michelle Sutton). So that rule being, my 10 oz IBS tuner was about 7" long and overhang the muzzle by about 5.5". The consideration here is that an improperly designed screw-on, of significant weight, balance has to be considered since on that particular tuner, which Jim Borden helped me design, when I made any adjustment at all, the POI would sometimes change as much as 1" at 100 yards.

.

jackie schmidt
03-02-2015, 07:55 AM
Perhaps the different perspectives regarding this subject are rooted in application.

When I started coming up with a idea for a tuner, the goal was always that it had to work within the parameters of a 10.5 pound NBRSA rifle. This greatly reduced the options, as at that time, most of my Rifles were right on weight.

The first thing I did was figure out how light of practice barrel I could get out of a standard LV blank. By leaving only1inch of "straight" on the chamber end, I was able to get a 21 1/2 inch barrel down to 78 ounces. That gave me about 5 ounces to play with.

I decided on a one piece design, on a vey fine thread, (36 tpi), with considerable contact. I also decide to use two 6-32 pinch bolts to tighten the tuner onto the thread in order to achieve a firm lock, but still be easy to tune at the line.

After playing with just a aluminum tuner, I decided that some type of dampener could be incorporated. I wanted a hard rubber compound that I could press onto the tuner body. I ended up using a brass shell marine bearing. The final tuner weighed right at 5 ounces.

It was simple, easy to adjust, and it worked. I have now started using a different dampener, as I found a very hard rubber compound used on tug boat bumpers that I could machine and press onto the tuner body, with a flared end to secure it dimly.

Since this has been a number of years ago, most have forgot all of the "tuner wars" of the mid 2000's. Many designs were tried, people tended to look at match reports to ascertain the true affectivness of what ever design they wanted to try.

The main thing was unless you could make something that would attach to a LV or Sporter and still make weight, it all became a moot point. It also had to be easy to adjust, sitting at the Bench, under match conditions.

Through the years, what I have found is a tuner will not make a mediocre barrel shoot like a great barrel. What it will allow you to do is get every thing out of a given barrel, whether in be a Factory Barrel or a full house Krieger Custom.

Another thing that a tuner can do is allow you to fine tune the characteristics of the tune within the tuning window. One mistake many shooters make is thinking that a flat shooting rifle is in tune. They keep shooting .350 long "caterpillars" straight across the target, or 1" ones at 200. The tuner will allow you to tweak a small amount of verticle into the tune so the Rifle is so not darned wind sensitive.

This is especially helpful in score shooting. 30BR's can be a nightmare to shoot if you are caught in that "Horizonal tune", where you physically can't see the small changes that cause the bullets to go a lot further than they should. If I find my 30 is too wind sensitive to the left and right, I will tweak the tuner, get a little verticle in the Rifle, and go from there.

It works. Perhaps not so much in Group Shooting, because if the group forms just outside the moth ball, it's not as big of a deal, the skill of the shooter can overcome this, as you can always chase that first shot.

But in score, you have to hit that 10, or that X, every time.

Here is a picture of the inside of one of my tuners.

http://benchrest.com/attachment.php?attachmentid=15927&stc=1&d=1425300893

jackie schmidt
03-02-2015, 07:57 AM
Barrel thread.

http://benchrest.com/attachment.php?attachmentid=15928&stc=1&d=1425301045

Boyd Allen
03-02-2015, 10:11 AM
Thanks Jackie,
That post was a jewel of solid information.
Boyd

mwezell
03-02-2015, 10:18 AM
Thanks Jackie,
That post was a jewel of solid information.
Boyd

Yes it was. Thank you Jackie.

mks
03-02-2015, 08:18 PM
Keith, again, unless I'm reading something wrong, we're still saying pretty much the same thing. I think you're referring to what's happening more behind the muzzle, that affects the angle, where I'm saying at the muzzle.

No, I am talking about the muzzle and its angle. That is what determines the launch angle for the bullet.


Wouldn't a short stiff barrel move faster?

No. Here are the equations. Increasing stiffness decreases amplitude in direct proportion: delta = F/k, where F is the recoil force and k is the stiffness. Increasing stiffness increases frequency in proportion to the square root: omega = sqrt(k/m) where m is the mass. Speed is proportional to the product of amplitude and frequency: s ~ delta * omega = F/sqrt(k * m). A stiffer barrel moves slower because its decrease in amplitude is much greater than its increase in frequency.

Long range guns need to move faster than short range for perfect compensation. It helps that they are longer. It would be difficult to tune, say, a 22" HV barrel for 600+ yards, because it is so stiff.

Fretka
03-03-2015, 01:27 AM
I can tell you how much the weight of a dime will bend your barrel! But I can't tell you for certain how that affects accuracy.

I have my doubts that a tuner changes vibrational frequencies, but it would certainly damp or amplify them. The driver that determines frequencies would be the initial primer pop and then propellant burn over time. I fear calculus is lurking here somewhere!

mks
03-03-2015, 08:36 AM
I can tell you how much the weight of a dime will bend your barrel! But I can't tell you for certain how that affects accuracy.

I have my doubts that a tuner changes vibrational frequencies, but it would certainly damp or amplify them. The driver that determines frequencies would be the initial primer pop and then propellant burn over time. I fear calculus is lurking here somewhere!

This equation shows that mass decreases frequency: omega = sqrt(k/m). Omega is the frequency. m is the mass. So frequency decreases in inverse proportion to the square root of mass. For a mass added to the end of beam (rifle barrel), here are the basics: http://iitg.vlab.co.in/?sub=62&brch=175&sim=1078&cnt=1 Yes, there is calculus in there.

So how much does a dime bend a barrel, and how did you measure it?

mwezell
03-03-2015, 09:43 AM
No, I am talking about the muzzle and its angle. That is what determines the launch angle for the bullet.



No. Here are the equations. Increasing stiffness decreases amplitude in direct proportion: delta = F/k, where F is the recoil force and k is the stiffness. Increasing stiffness increases frequency in proportion to the square root: omega = sqrt(k/m) where m is the mass. Speed is proportional to the product of amplitude and frequency: s ~ delta * omega = F/sqrt(k * m). A stiffer barrel moves slower because its decrease in amplitude is much greater than its increase in frequency.

Long range guns need to move faster than short range for perfect compensation. It helps that they are longer. It would be difficult to tune, say, a 22" HV barrel for 600+ yards, because it is so stiff.

Alright, so more amplitude is good, and tuners give more amplitude, right?:D
Also, if time and distance = speed, then more amplitude at a given frequency, means it must move with more speed.

Now, even if speed is constant, in which pic below would it be possible to have the least total muzzle displacement if the speed were constant and equal, as is time and distance? We have to use our imagination a little here, but assume both shapes are the same in circumference.

Obviously, if we time bullet exit to the top or bottom of the image on the left, the total displacement, at the same speed, will cover less area than in the pic of the circle..which BTW, I simply pulled out of the air. Perhaps you have a better analogy to convey your thoughts?

15930

The pic is an exaggeration and not meant to be accurate, but it does depict what happens to muzzle displacement with a tuner. That being to bias it's angular change vertically, vs. no tuner, creating areas at top and bottom where, while speed may increase, the area covered by total displacement would appear to be greatly lessened.

Boyd Allen
03-03-2015, 12:04 PM
We know that shots in a group vary in velocity, therefore any successful scheme should take this into consideration. The work that Varmint Al (a very talented retired engineer ) seems to demonstrate that it is not at the peak that we want bullets to exit, but rather just to the left of the peak of on a graph of a projection of the muzzles rise on a downrange target. This timing would seem to compress vertical differences on target of shots of differing velocities. Essentially we need to slow the initial rise of the muzzle to the point that the bullet can exit in the desired part of its cycle. Varmint Al showed three methods for accomplishing this. add weight at the muzzle (quite a bit if I remember correctly) lengthen the barrel, and thinning the barrel in the middle. IMO there is a lot more work that cam be done with barrel contours for use both with and without tuners. Some years back, I asked Harold Vaughn about the relation between barrel mass, stiffness, and accuracy. He told me that while there was a positive relation between increased mass and accuracy, that that was not necessarily the case for stiffness. Another fellow that I knew that did some work relating to barrel vibration was Don Jackson. One time, on a practice day before a match, he was testing with an accelerometer taped to the muzzle of his rifle's barrel, with an oscilloscope sitting on the bench beside it. The rifle had a metal stock of his own making, and a Panda action. I asked him if the position of the scope, and or rings on the scope changed the vibration pattern. He said that it did. Think about that one for a while. Perhaps tuners do not have to be on the barrel. Recently Bill Calfee has done some interesting work involving an adjustable weight at the back of his scope, with the scope mounted with a single ring, on a base on the front receiver ring. He has taken some flack on this, and I am not a Calfee worshiper, but I believe that he is sincere and that his work in this area may demonstrate something interesting that may have other applications, when applied in a different manner.

mks
03-03-2015, 01:21 PM
15930

Mike,
Your drawing helps illustrate what we want the muzzle to do. If it is following a circle, then we get horizontal dispersion along with positive or negative vertical compensation. So to reduce the horizontal dispersion, we would pick the oval. Now which part of the oval? At the top or bottom of the oval where the muzzle has little vertical motion, slow and fast bullets come out of the muzzle at nearly the same vertical angle. So the slow ones hit low on the target and the fast ones high. This produces vertical dispersion, which is not good. At the same time, the muzzle has its fastest horizontal velocity here, so we also get the greatest horizontal dispersion. On the other hand, on the side of the oval where the muzzle is rising, slow bullets that exit the muzzle later are launched at a higher angle, so they have a chance of striking the target at the same elevation as the fast bullets. We tend to get the smallest vertical dispersion here. Right in the middle (half way between the top and the bottom), the horizontal velocity goes to zero, so this point minimizes horizontal dispersion also.

What we can't tell from just the shape of the curve it what velocity the muzzle has. There is one perfect muzzle angular velocity that will provide perfect compensation (zero vertical dispersion) at a given yardage, load and atmospheric conditions. Ideally we want the muzzle angle to be rising straight up at that perfect rate, with no motion horizontally for zero horizontal dispersion as well.

Delta = F/k, so tuner mass doesn't directly affect amplitude delta. It does have a secondary effect through increasing the sag in the muzzle due to gravity, which increases force F (or more accurately, the moment arm of the recoil moment). A more direct way to increase amplitude is to decrease stiffness k, or lower the CG of the rifle to get more recoil moment.

Cheers,
Keith

Joe Woosman
03-03-2015, 01:33 PM
I know my opinion carries little weight here but I have a problem with the theory of positive compensation and the magic in a good tune being the barrels ability to compensate for velocity variations. I understand mathematically it can be shown to make sense. However, with the new super precision loading scales and the ability of people to load to single digit extreme spreads, why has this not proven to be a solution to short range tuning? Theoretically, if you have no velocity variation, positive compensation can do nothing for you.

Now let’s suppose there are variations in the bullets ignition to muzzle exit time but low velocity spread. I mean, how can there not be with the variables in ignition and friction? We just can’t measure it like we can velocity. Theoretically in this case, bullets exiting at a higher rising muzzle velocity, (or angle), would produce greater dispersion with exit timing variations versus a muzzle that was slowed nearer a “stop”.

Outside of computer simulation, has there been any measured confirmation that positive compensation is indeed happening??

mks
03-03-2015, 02:05 PM
I know my opinion carries little weight here but I have a problem with the theory of positive compensation and the magic in a good tune being the barrels ability to compensate for velocity variations. I understand mathematically it can be shown to make sense. However, with the new super precision loading scales and the ability of people to load to single digit extreme spreads, why has this not proven to be a solution to short range tuning? Theoretically, if you have no velocity variation, positive compensation can do nothing for you.

Now let’s suppose there are variations in the bullets ignition to muzzle exit time but low velocity spread. I mean, how can there not be with the variables in ignition and friction? We just can’t measure it like we can velocity. Theoretically in this case, bullets exiting at a higher rising muzzle velocity, (or angle), would produce greater dispersion with exit timing variations versus a muzzle that was slowed nearer a “stop”.

Outside of computer simulation, has there been any measured confirmation that positive compensation is indeed happening??

Joe,
You are correct about zero velocity spread not needing compensation. The smallest group I ever shot was with a rifle that had essentially no compensation, because its CG was level with the bore. The other argument against worrying about compensation is that it doesn't make much difference at short range even if you have a sizable ES. I have done the calculations. It's not easy, because most external ballistics programs don't allow you to input muzzle angle. But if I recall correctly, the difference is in the 10's of thousandths range. The counter argument, though, is that every little bit counts. I know I have lost X's, points and matches where 0.010" would have made a difference.

Friction slows down muzzle velocity and exit time, so it should be subject to compensation the same as charge weight. Ignition and the pressure curve, and more, may have random effects that cause dispersion that can't be compensated.

Kolbe posted some 22RF groups before and after tuning that will make your jaw drop. For my CF tests, the compensation is not very evident by eye. You have to measure carefully.

Cheers,
Keith

mwezell
03-03-2015, 02:25 PM
Mike,
Your drawing helps illustrate what we want the muzzle to do. If it is following a circle, then we get horizontal dispersion along with positive or negative vertical compensation. So to reduce the horizontal dispersion, we would pick the oval. Now which part of the oval? At the top or bottom of the oval where the muzzle has little vertical motion, slow and fast bullets come out of the muzzle at nearly the same vertical angle. So the slow ones hit low on the target and the fast ones high. This produces vertical dispersion, which is not good. At the same time, the muzzle has its fastest horizontal velocity here, so we also get the greatest horizontal dispersion. On the other hand, on the side of the oval where the muzzle is rising, slow bullets that exit the muzzle later are launched at a higher angle, so they have a chance of striking the target at the same elevation as the fast bullets. We tend to get the smallest vertical dispersion here. Right in the middle (half way between the top and the bottom), the horizontal velocity goes to zero, so this point minimizes horizontal dispersion also.

What we can't tell from just the shape of the curve it what velocity the muzzle has. There is one perfect muzzle angular velocity that will provide perfect compensation (zero vertical dispersion) at a given yardage, load and atmospheric conditions. Ideally we want the muzzle angle to be rising straight up at that perfect rate, with no motion horizontally for zero horizontal dispersion as well.

Delta = F/k, so tuner mass doesn't directly affect amplitude delta. It does have a secondary effect through increasing the sag in the muzzle due to gravity, which increases force F (or more accurately, the moment arm of the recoil moment). A more direct way to increase amplitude is to decrease stiffness k, or lower the CG of the rifle to get more recoil moment.

Cheers,
Keith

Lots of good points Keith. Good post.

mwezell
03-03-2015, 02:32 PM
Joe,
You are correct about zero velocity spread not needing compensation. The smallest group I ever shot was with a rifle that had essentially no compensation, because its CG was level with the bore. The other argument against worrying about compensation is that it doesn't make much difference at short range even if you have a sizable ES. I have done the calculations. It's not easy, because most external ballistics programs don't allow you to input muzzle angle. But if I recall correctly, the difference is in the 10's of thousandths range. The counter argument, though, is that every little bit counts. I know I have lost X's, points and matches where 0.010" would have made a difference.

Friction slows down muzzle velocity and exit time, so it should be subject to compensation the same as charge weight. Ignition and the pressure curve, and more, may have random effects that cause dispersion that can't be compensated.

Kolbe posted some 22RF groups before and after tuning that will make your jaw drop. For my CF tests, the compensation is not very evident by eye. You have to measure carefully.

Cheers,
Keith

I agree, but if we tune as if we're tuning for positive compensation, we're also at a point where muzzle angle and or it's position at bullet exit has very near its least amount of movement. Win..win. IMO.

Joe Woosman
03-03-2015, 02:35 PM
I have done the calculations. It's not easy, because most external ballistics programs don't allow you to input muzzle angle. But if I recall correctly, the difference is in the 10's of thousandths range.

Keith,

With the "10's of thousandths range", are we talking a few .010" or double digits up to .100"?

Can some of those using tuners describe what they see in group size when adjusting the tuner? I have never used one.

jackie schmidt
03-03-2015, 03:26 PM
Keith,

With the "10's of thousandths range", are we talking a few .010" or double digits up to .100"?

Can some of those using tuners describe what they see in group size when adjusting the tuner? I have never used one.

Joe, I have fired thousands of rounds in practice, and in competition, using a tuner on a short range Benchrest Rifle. Many in practice over a chronograph.

First, velocity spread seems to have little to do with a Benchrest Rifles ability to shoot competitive groups, which for the sake of argument, we will say is sub.200 at 100 yards. With my Rail Gun, I have shot 10 shot groups in practice, over a chronograph, at the sub .150 level with a velocity spread of close to 25fps.

I always go to the line with what I hope is the tune that produces the smallest groups, regardless of any other parameters of ballistic performance.

As for what you can do to groups with a tuner. If you have a good barrel, and a good tune, say with a agging capability at about .150, I seriously doubt you could crank more than .250 to .280 worth of bad grouping into it with a tuner. And most of that will be in the verticle plain.

I have done it. I have taken my LV that was shooting quite well on a specific day, and turned the tuner until it got ragged. But, unless I did something like ignore the flags, or change the load, there is no way it was suddenly going to start shooting "fours". The groups will usually start going diagnol in the mid to high "two" range.

If you think about it, when speaking in terms of 100/200 yard Benchrest, that's a lot.

mwezell
03-03-2015, 04:20 PM
Joe, I have fired thousands of rounds in practice, and in competition, using a tuner on a short range Benchrest Rifle. Many in practice over a chronograph.

First, velocity spread seems to have little to do with a Benchrest Rifles ability to shoot competitive groups, which for the sake of argument, we will say is sub.200 at 100 yards. With my Rail Gun, I have shot 10 shot groups in practice, over a chronograph, at the sub .150 level with a velocity spread of close to 25fps.

I always go to the line with what I hope is the tune that produces the smallest groups, regardless of any other parameters of ballistic performance.

As for what you can do to groups with a tuner. If you have a good barrel, and a good tune, say with a agging capability at about .150, I seriously doubt you could crank more than .250 to .280 worth of bad grouping into it with a tuner. And most of that will be in the verticle plain.

I have done it. I have taken my LV that was shooting quite well on a specific day, and turned the tuner until it got ragged. But, unless I did something like ignore the flags, or change the load, there is no way it was suddenly going to start shooting "fours". The groups will usually start going diagnol in the mid to high "two" range.

If you think about it, when speaking in terms of 100/200 yard Benchrest, that's a lot.

Actually, I see teens in good tune and high 3's to low 4's when completely out of tune. Realistically, I've never been that far out of tune due to conditions, though. It's just that the tuner will take it that far out. It could very well be that different tuner weight and/or barrel stiffness is why you don't see as much with yours. That's not a bad thing in itself, though..probably just a difference between tuner designs and the gun they're on. As long as it will bring the groups down, repeatably and consistently, I think that's what's most important.

mks
03-03-2015, 04:52 PM
Keith,

With the "10's of thousandths range", are we talking a few .010" or double digits up to .100"?

Can some of those using tuners describe what they see in group size when adjusting the tuner? I have never used one.

Joe,
Here is an example for a 0.308" bullet with BC of 0.366. For a spread of 3030 to 3040 fps with a fixed launch angle, the spread is 0.013" at 100 and 0.057" at 200. I have never gotten ES that low for 10 shots, let alone 50 shots for a full match. For a spread on the high side of 3020 to 3050 fps with the same launch angle, the spread is 0.040" at 100 and 0.172" at 200. One can judge according to their own ES, but the 200 yard dispersion is getting up there in the significant range.

Twist the tuner a little at a time, and the groups go from horizontal to round to vertical to round and back again. The round groups tend to be the smallest. It is repeatable, but not necessarily at the same settings as conditions change.

mwezell
03-03-2015, 05:22 PM
Joe,
Here is an example for a 0.308" bullet with BC of 0.366. For a spread of 3030 to 3040 fps with a fixed launch angle, the spread is 0.013" at 100 and 0.057" at 200. I have never gotten ES that low for 10 shots, let alone 50 shots for a full match. For a spread on the high side of 3020 to 3050 fps with the same launch angle, the spread is 0.040" at 100 and 0.172" at 200. One can judge according to their own ES, but the 200 yard dispersion is getting up there in the significant range.

Twist the tuner a little at a time, and the groups go from horizontal to round to vertical to round and back again. The round groups tend to be the smallest. It is repeatable, but not necessarily at the same settings as conditions change.

That brings up another misconception..at least with some tuner/gun combinations. I often read people say that tuners only take out vertical. I find this untrue as when completely out of tune, big round 5 shot groups are common. Then the groups tend to stairstep diagonally. Next is where they go to just vertical before sucking down to just a bughole. This too may be somewhat dependent on tuner/gun idiosyncracies , but I see no reason why we should expect tuners to only remove/induce vertical, other than that I don't get that far out of tune from conditions alone...or never have. The only times I've seen the gun be that far out is when starting out or not knowing a baseline for tuner setting on a specific gun, due to taking it off or randomly moving it without knowing where it was set before.

The nice thing here is that it takes just a few shots to fix it..It's very typical for the range of tuner movement between in and all the way out of tune, with my tuner and a HV contour barrel of nominally standard lengths to be 4 marks. Thing is, that 4 marks in either direction, to be very close to your sweet spot, again. Now think about this for a second. If 4 marks on either side of your best setting takes you completely out of tune..AND there are 32 marks on the tuner..we have a one in four chance of being at or very near our sweet spot..basically anywhere along the tuners range of adjustment. Admittedly, this isn't 100% linear, but it's close.

Think about what I just said. With my tuner, it is typical to never be more than 4 marks from a sweet spot!! Let me repeat that..It is TYPICAL to never be more than 4 marks out at any point. Now, add to that, that realistically, I never use more than about two marks to maintain tune through any and all conditions I've ever encountered while shooting with a tuner.
I hope the picture I'm drawing here is becoming clearer now. That picture is just how EASY it is to use a tuner. These numbers are based what I've found to be true every time with my tuners, on many different guns with std hv contour barrels. The numbers are exact between different guns, but very, very close.

This is probably the most important point I'd like to make in this thread. That being just how easy using a tuner really is.

mks
03-03-2015, 05:24 PM
I agree, but if we tune as if we're tuning for positive compensation, we're also at a point where muzzle angle and or it's position at bullet exit has very near its least amount of movement. Win..win. IMO.

Mike,
You seem to be stuck on Calfee's stopped muzzle mantra. If the muzzle is not moving, then you will have vertical dispersion due to velocity spread. To have perfect compensation and zero vertical dispersion due to velocity spread, the muzzle angle must be rising, and fast. Faster than typical short range BR rifles move, in my limited testing.

Let's think about it in terms of the two bullets, one fast and one slow reaching the muzzle in a bit over 1 millisecond after ignition. If the slow one takes 1% longer corresponding to, for instance, a drop of 30 fps compared to the 3000 fps MV for the fast bullet, then the delay in exit time is about 10 microseconds. During that time, the muzzle must rise to the new, higher launch angle necessary for the slower bullet to hit the target at the same point as the faster bullet. 10 microseconds is a very short time, so a lollygagging barrel is not going to get the job done.

Cheers,
Keith

mks
03-03-2015, 05:35 PM
That brings up another misconception..at least with some tuner/gun combinations. I often read people say that tuners only take out vertical.

Good point. The adjustments made during a match are fine tuning, which works on horizontal and vertical. Positive compensation isn't something you get by adjusting the tuner by a few marks. It takes large movement of the tuner and/or redistributing the weight in the rifle.

jackie schmidt
03-03-2015, 06:01 PM
I addressed that in my post #52 where I discussed that dreaded "Horizonal tune".

By the way, what are the Threads per Inch of the moveable part of your tuner.? Mine are 36 TPI, which is a little over .007 inch advance per 1/4 turn.

Jerry H
03-03-2015, 06:02 PM
Actually, a pressure trace chronograph will show variations in rise time, which in my experience, is significant to group dispersion. This is somewhat independent of muzzle velocity variation that indicates little of the grouping potential of a given load.

mwezell
03-03-2015, 06:07 PM
Mike,
You seem to be stuck on Calfee's stopped muzzle mantra. If the muzzle is not moving, then you will have vertical dispersion due to velocity spread. To have perfect compensation and zero vertical dispersion due to velocity spread, the muzzle angle must be rising, and fast. Faster than typical short range BR rifles move, in my limited testing.

Not at all, Keith. I very much believe that you're correct in that the muzzle never stops, but I also believe that it covers a lot less area while it's at near the top and bottom..even if it doesn't slow at all. That's why I posted the pics. If the muzzle moves anywhere close to the elongated pic on the left, it certainly isn't covering much area if tuned for bullet exit just prior to max vertical displacement. It's just making a u-turn, so to speak.



Let's think about it in terms of the two bullets, one fast and one slow reaching the muzzle in a bit over 1 millisecond after ignition. If the slow one takes 1% longer corresponding to, for instance, a drop of 30 fps compared to the 3000 fps MV for the fast bullet, then the delay in exit time is about 10 nanoseconds. During that time, the muzzle must rise to the new, higher launch angle necessary for the slower bullet to hit the target at the same point as the faster bullet. 10 nanoseconds is a very short time, so a lollygagging barrel is not going to get the job done.

Cheers,
Keith
Is my math wrong? Would that not be 10,000 nanoseconds?;) Still an unimaginably short time.

mwezell
03-03-2015, 06:09 PM
I addressed that in my post #52 where I discussed that dreaded "Horizonal tune".

By the way, what are the Threads per Inch of the moveable part of your tuner.? Mine are 36 TPI, which is a little over .007 inch advance per 1/4 turn.

Mine is .900 x 32 tpi, Jackie.

mwezell
03-03-2015, 06:12 PM
Actually, a pressure trace chronograph will show variations in rise time, which in my experience, is significant to group dispersion. This is somewhat independent of muzzle velocity variation that indicates little of the grouping potential of a given load.

Good point. I need to send mine back for repairs and updating.

mks
03-03-2015, 10:16 PM
Is my math wrong? Would that not be 10,000 nanoseconds?;) Still an unimaginably short time.

Yes, I am off by a prefix. It is 10 microseconds. An eternity compared to nanoseconds! Sorry about that.

mks
03-04-2015, 09:13 AM
Here are some more exact numbers: For a 0.308" bullet with BC of 0.366 in a 22" barrel, muzzle velocity of 3029 fps and an air temperature of 80F, for perfect compensation at 100 yards, the required muzzle angular velocity is about 18 rpm, at 200 yards 38 rpm, and 300 yards 61 rpm. The speeds don't sound so impressive compared to, for instance, electric motors, but they are still faster than typical BR rifles move. Notice also the large difference among the yardages. To be perfect, the rifle needs not just a small tuner adjustment between yardages, but a large change in weight/stiffness distribution.

Joe Woosman
03-04-2015, 11:15 AM
Keith,

Have you found a method of testing the amount of positive compensation a rifle setup provides?

Fretka
03-04-2015, 03:28 PM
This equation shows that mass decreases frequency: omega = sqrt(k/m). Omega is the frequency. m is the mass. So frequency decreases in inverse proportion to the square root of mass. For a mass added to the end of beam (rifle barrel), here are the basics: http://iitg.vlab.co.in/?sub=62&brch=175&sim=1078&cnt=1 Yes, there is calculus in there.

So how much does a dime bend a barrel, and how did you measure it?


Comparing a barrel with the mass of a tuner to that without, clearly mass is changed but movement of existing mass would not change the fundamental frequency but would damp or amplify either the fundamental or harmonics (I think)! IOW tune it.

Holographic interferometry, 6 whole wavelengths of 632 nanometer light wavicles (!?) Fascinating to watch as I did use a method that allowed live measurements to be obtained.
Fretka

mks
03-04-2015, 03:29 PM
Keith,

Have you found a method of testing the amount of positive compensation a rifle setup provides?

Yes, a ladder test. Shoot a range of loads with their corresponding differences in muzzle velocity. Typically the hotter, faster loads print higher on target. Shift weight/stiffness around on the rifle until they shoot to the same elevation, at least over a part of the range.

Joe Woosman
03-04-2015, 05:01 PM
I have seen what Francis described many times. I recently did some extensive ladder testing with a long barrel 300WSM. There were distinct loads where the vertical was nearly gone but would then produce horizontal strings like Jackie referred to earlier. The loads where the vertical came together were at different elevations on the target and did not correlate with velocity.

Joe Woosman
03-04-2015, 05:43 PM
Joe,
Here is an example for a 0.308" bullet with BC of 0.366. For a spread of 3030 to 3040 fps with a fixed launch angle, the spread is 0.013" at 100 and 0.057" at 200. I have never gotten ES that low for 10 shots, let alone 50 shots for a full match. For a spread on the high side of 3020 to 3050 fps with the same launch angle, the spread is 0.040" at 100 and 0.172" at 200. One can judge according to their own ES, but the 200 yard dispersion is getting up there in the significant range.

Also of note, I was shooting 215 Bergers with a BC of .696 from 2700 to 2900 at 100 yards with up to 30fps spreads. Comparing this to your above example of .040 at 100 I would say I am not seeing any effects of positive compensation but some sort of wave is moving the groups up and down with velocity. I just don't see how we can measure or confirm the effects of positive compenstion while the above is happening.

mks
03-04-2015, 07:19 PM
Francis and Joe,
Because of the complexity of muzzle motion, I don't believe that it is possible for a barrel to behave the same over a broad range of loads. That is why I said "at least over part of the range." What I am talking about is the general trend of the results over a wide range. Below is what I think is a typical result. Even though there are "stair steps" where the elevation is close to the same for a few charges, the general trend is upward with greater charge weight. Over two of the stair steps, there is nearly perfect compensation for a 0.4 grain range at this yardage (100). If this isn't typical of your results, then I would be interested to see yours.

15939

After modification, the same rifle produced the results below at the same yardage. The downward trend (of the linear fit) is within about 10% of being perfectly compensated for 200 yards. There are three windows of 0.4 grains where the black average curve fits the downward trend fairly closely. Note that the modification completely changed the overall trajectory of the results. If we were to pick one, the modified rifle is better tuned, because of the greater vertical dispersion of uncompensated shots at longer yardage. But it would be better to have perfect compensation at both yardages, for which we need a different tune at each yardage.

15940

Cheers,
Keith

mks
03-04-2015, 07:34 PM
Also of note, I was shooting 215 Bergers with a BC of .696 from 2700 to 2900 at 100 yards with up to 30fps spreads. Comparing this to your above example of .040 at 100 I would say I am not seeing any effects of positive compensation but some sort of wave is moving the groups up and down with velocity. I just don't see how we can measure or confirm the effects of positive compenstion while the above is happening.

Joe,
You have roughly double the BC, so the dispersion will be less without compensation. But all else being controlled, and with a stopped muzzle, faster bullets must track higher monotonically. That you are seeing waves with increasing MV is evidence of varied compensation. If you are finding stair steps where the elevation is constant over some range of MV, then you have found perfect compensation at that yardage.

Cheers,
Keith

JerrySharrett
03-05-2015, 07:25 PM
One more comment for shooters new to tuners. Don't know if this applies to light weight tuners but it does to the heavy ones. If you are taking a known, good, fixed load like 29.2 V133 you will find that a given barrel will have multiple sweet spots. You just have to pick one you think is good enough since you could shoot a barrel out trying to decide.

Rimfire shooters use heavy tuners and will tell you they find multiple sweet spots, but, a rimfire barrel is good for a few to several thousand rounds where most centerfire barrels are gone in a few hundred rounds.

.

adamsgt
03-05-2015, 08:16 PM
where most centerfire barrels are gone in a few hundred rounds.

.

Well, I might as well quit then. It takes me that many rounds to find a bullet and load that works reasonably well. :confused: Oh well.

Dusty Stevens
03-06-2015, 01:43 PM
Like jerry said find a known good load and tweak it. If it dont shoot get a new barrel. Shoot a normal load or get beat by one

mwezell
03-06-2015, 02:17 PM
Like jerry said find a known good load and tweak it. If it dont shoot get a new barrel. Shoot a normal load or get beat by one

Dusty, I don't see where he said exactly that, but it's especially true with tuners. A known good load can virtually always be tuned to shoot with just a tweak of the tuner.

This is from experience. I'm not pulling anything from my backside. If I can use a tuner, anyone can. They really are as easy to use as I say.

This is a great thread, but we tend to get into the why's and how's, forgetting that it's a lot easier to do than to explain why and how. Someday all of that'll will be figured out. Til then, I'm gonna shoot with one, because it's much easier than tuning with powder charge and seating depth. It may sound too good to be true..but it's true.

All that matters is that there ARE easily found spots on the tuner where the gun will shoot..and that within a very small range of motion, the gun can be kept shooting through condition changes that would otherwise dictate a load change to maintain tune.--M

Joe Woosman
03-06-2015, 03:43 PM
Joe,
You have roughly double the BC, so the dispersion will be less without compensation. But all else being controlled, and with a stopped muzzle, faster bullets must track higher monotonically. That you are seeing waves with increasing MV is evidence of varied compensation. If you are finding stair steps where the elevation is constant over some range of MV, then you have found perfect compensation at that yardage.

Cheers,
Keith

Keith,
I think I understand you at this point. If there is stable, repeatable vertical impact over a range of MV that is less dispersed than the mathematical value predicted due to drag, there must be a positive compensation happening. I can buy that.

In my ladder test I was talking about, the lowest vertical value loads, (approximately .2), repeated about every 1-1/2 grains shooting in .5 grain increments. The .5 grain loads just prior showed the greatest uniform vertical string, (approximately .5). I don't believe even zero velocity spread could improve the group here. Since there is a clear vertical pattern happening, and that which is much greater than velocity spread can account for, there must be something much more critical to the relationship between bullet exit timing and barrel wave pattern. It does seem to me that if the muzzle were in the same exact position each shot the groups could be very small even with no vertical compensation. (I'm not promoting the "stopped muzzle" theory either).

Dusty Stevens
03-06-2015, 09:13 PM
Dusty, I don't see where he said exactly that, but it's especially true with tuners. A known good load can virtually always be tuned to shoot with just a tweak of the tuner.

This is from experience. I'm not pulling anything from my backside. If I can use a tuner, anyone can. They really are as easy to use as I say.

This is a great thread, but we tend to get into the why's and how's, forgetting that it's a lot easier to do than to explain why and how. Someday all of that'll will be figured out. Til then, I'm gonna shoot with one, because it's much easier than tuning with powder charge and seating depth. It may sound too good to be true..but it's true.

All that matters is that there ARE easily found spots on the tuner where the gun will shoot..and that within a very small range of motion, the gun can be kept shooting through condition changes that would otherwise dictate a load change to maintain tune.--M

Post 88- that is what he meant by starting with a known good load. Some people will try to work up a load of some other powder with wolf primers in sako cases with a bullet made by somebody that makes 300/yr.
When you have a squirrelly load and then throw a tuner in there with a bad scope itll make you want to rub feces in your hair.

mks
03-06-2015, 09:41 PM
Keith,
I think I understand you at this point. If there is stable, repeatable vertical impact over a range of MV that is less dispersed than the mathematical value predicted due to drag, there must be a positive compensation happening. I can buy that.

In my ladder test I was talking about, the lowest vertical value loads, (approximately .2), repeated about every 1-1/2 grains shooting in .5 grain increments. The .5 grain loads just prior showed the greatest uniform vertical string, (approximately .5). I don't believe even zero velocity spread could improve the group here. Since there is a clear vertical pattern happening, and that which is much greater than velocity spread can account for, there must be something much more critical to the relationship between bullet exit timing and barrel wave pattern. It does seem to me that if the muzzle were in the same exact position each shot the groups could be very small even with no vertical compensation. (I'm not promoting the "stopped muzzle" theory either).

I ran your conditions through my calculator, and with a fixed muzzle, you would have the 2900 fps load striking 0.32" higher than the 2700 fps. So yes, you could have small groups at 100 without compensation. At 600 yards, though, no compensation would get you a 13" vertical spread.

0.32"/(2900-2700) = 0.0016"/fps. If over any interval you see a smaller rise, you have positive compensation.

JerrySharrett
03-07-2015, 05:55 AM
Post 88- that is what he meant by starting with a known good load. Some people will try to work up a load of some other powder with wolf primers in sako cases with a bullet made by somebody that makes 300/yr.
When you have a squirrelly load and then throw a tuner in there with a bad scope itll make you want to rub feces in your hair.

That is exactly what I mean Dusty, thanks. Everyone who shoots the PPC, for example, a lot, like for years, pretty much have a standard starting place, i.e. a known good load.

Best example Tony Boyer. Mr Boyer, who has more than 3 times the HOF points of the next three on that list combine can, with his known good load, with confidence, test 15-20 barrels within 20 shots per barrel to see which he plans to keep for that season.



.

mwezell
03-07-2015, 07:18 AM
Post 88- that is what he meant by starting with a known good load. Some people will try to work up a load of some other powder with wolf primers in sako cases with a bullet made by somebody that makes 300/yr.
When you have a squirrelly load and then throw a tuner in there with a bad scope itll make you want to rub feces in your hair.

I couldn't agree more Dusty. But say your load typically changes, over the course of a match, from 29.2-30.0 gr. That's a range of charges that are good in your gun at varying conditions, temps, etc. Tuners make it possible to load any of those charges, assuming no pressure issues, and shoot that same single charge all match long, without changing powder charge/seating depth to maintain tune.

Simply load up 29.2 and maintain tune by just nudging the tuner..when or if needed. Or, you could do as Mr. Bukys, and still tune traditionally, but not see the sharp and sometimes frequent fall offs in tune that can happen, particularly with a ppc and 133. The benefit of a tuner here, is the wider tune window.

But as you said, a tuner will no more fix a gun problem than it will a bad bullet problem.-Mike

tim in tx
03-08-2015, 05:05 PM
Great thread guys,enjoyed the reading very much .

Tim in Tx

mwezell
03-08-2015, 05:44 PM
Great thread guys,enjoyed the reading very much .

Tim in Tx

I agree Tim! Very little or no bickering, but lots of good info from some very smart people. It's hard to discuss tuners and not have infighting. This one defies that for the most part and is mostly in terms that the majority of us can understand. That's hard to do, also. These threads about tuners can quickly get into terminology that causes people that don't understand it, to lose interest and fall back on arguments that they've heard as being gospel.

I have an interest in knowing all I can about how they work, but realistically, it's so easy to make them work, understanding the why's and how's is not nearly as important as some make it to be.

The biggest hurdle, IMHO, to using tuners in cf is weight limits in LV class. For that reason, and to make them more viable for the most popular class in cf(LV), to get more people to use and experiment with tuners, we either need lighter tuners or more tuner friendly barrel profiles...or both.

I do truly feel that if more shooters in that class started using them, it'd snowball fairly rapidly.

The biggest difference I see in cf vs. rf is that some feel like the stopped muzzle theory is workable. I don't, but that's what these discussions are good for. As I understand that theory, the bullet exit is timed with the vibrational node where that node is moved to the muzzle and the muzzle is "stopped". It's my understanding that this is physically impossible, as moving that node to the end of a cantilevered beam isn't possible.

Perhaps Keith or someone can elaborate on this.--Mike

Boyd Allen
03-08-2015, 06:46 PM
That whole stopped muzzle thing is a rimfire Calfeeism, and (IMO)does not comport with CF theory that is currently in use. To move a node to the muzzle, there has to be sufficient mass extending past it, and I do not believe that any of the tuners that are currently being use for CF work have that feature. What I think is happening in the CF world is that tuners are being used to modify the frequency of the barrels vibration during firing, so that the bullet will exit at the desired point in the cycling of muzzle motion. Beyond this, with some designs, there are attempts to damp spurious vibrations.

Chism G
03-08-2015, 08:34 PM
Something tells me that if we spent more time using tuners in actual Competition,we would know more about how they work.




Glenn

mwezell
03-08-2015, 09:16 PM
Something tells me that if we spent more time using tuners in actual Competition,we would know more about how they work.




Glenn Absolutely Glenn! It may or may not help with the physics behind them but I agree that we'd learn a lot if more people try them.

Dusty Stevens
03-08-2015, 09:41 PM
Mike i know you use the science of particle dampening- have you tried other things? Different powders, mercury, glycerine, glycol, oil? I have an extensive background on balancing rotating machinery and those items mentioned are some of the things we use

Matt P
03-09-2015, 07:09 AM
Just to add something a little different, I have recently fitted a "barrel weight" to customers F Class gun that he was having trouble getting it shoot consistently (shoot well one day and terrible the next), so we glued on a 600 gram weight on the end of the barrel (flush with the end, not overhanging and not adjustable), well it turned it from very fussy to a rifle with a huge tune window.
Regards
Matt P

mwezell
03-09-2015, 08:31 AM
Mike i know you use the science of particle dampening- have you tried other things? Different powders, mercury, glycerine, glycol, oil? I have an extensive background on balancing rotating machinery and those items mentioned are some of the things we use

Dusty, I considered oils and mercury, as well as springs and weights. As mentioned earlier, Bukys' rubber on his tuner is what got me headed down the path of finding a more efficient damping media than just a hunk of steel or aluminum on the end of the barrel. After pretty extensive research, two methods kept coming back up, tuned mass and particle dampening. Tuned mass dampening, in very simple form, would be a spring attached to the barrel with a weight suspended by it. Practicality was the issue here, as was thermal stability of springs. Somewhat relative was the work some had previously done with opposing magnets. But particle damping won out due to effectiveness and feasibility. I tested different particle medias, determining that what worked best was extremely fine and dense, so tungsten powder got the nod. I wish something cheaper had worked as well.:eek:

I forget what ultimately ruled out liquids, but I did study the concept before going the pd route. Perhaps it's worth testing. I do distinctly remember an analogy running through my head about an excited tuning fork being submerged in water, oil and tungsten powder..for some reason. Hopefully that analogy helps you with why I decided on pd and tungsten powder.

There was already extensive and expensive research done with particle dampening, comparing it's effectiveness to other means as well as other mediums used in pd. That certainly plays a part, when the research is already there, and just needed an application relative to barrel dampening.--Mike

mwezell
03-09-2015, 08:31 AM
Just to add something a little different, I have recently fitted a "barrel weight" to customers F Class gun that he was having trouble getting it shoot consistently (shoot well one day and terrible the next), so we glued on a 600 gram weight on the end of the barrel (flush with the end, not overhanging and not adjustable), well it turned it from very fussy to a rifle with a huge tune window.
Regards
Matt P

Amazing, isn't it?

Pete Wass
03-10-2015, 11:48 AM
Some assumptions must be accepted to what I am about to say. On a thread on another forum a lad who has been winning indoor rim fire matches with big scores; some of them perfect scores, describes his rifle's components. He is using a tuner that is nearly three times heavier than most others use. The assumptions being that a rifle shot is a rifle shot, regardless of caliber and powder charge and that a rifle barrel is a rifle barrel.

What I find interesting is the tuner weight. While I have been able to tune 21.5" 30 caliber barrels with 3 or 4 ounces, those seem to be finicky, from my experience. Not all the time but under some conditions. While it is probably impossible for CF folks to use 30 or 40 oz to tune a barrel, I am wondering if anyone has ever gone in that direction? More in line with "Positive Compensation" perhaps?

Thanks,

Pete

mwezell
03-10-2015, 12:51 PM
Some assumptions must be accepted to what I am about to say. On a thread on another forum a lad who has been winning indoor rim fire matches with big scores; some of them perfect scores, describes his rifle's components. He is using a tuner that is nearly three times heavier than most others use. The assumptions being that a rifle shot is a rifle shot, regardless of caliber and powder charge and that a rifle barrel is a rifle barrel.

What I find interesting is the tuner weight. While I have been able to tune 21.5" 30 caliber barrels with 3 or 4 ounces, those seem to be finicky, from my experience. Not all the time but under some conditions. While it is probably impossible for CF folks to use 30 or 40 oz to tune a barrel, I am wondering if anyone has ever gone in that direction? More in line with "Positive Compensation" perhaps?

Thanks,

Pete

Pete, I've tested different weight tuners quite a bit. Soon, I hope to have vibration analysis completed. This is one that we have not yet tested. IME, more weight does give what you are seeing...wider tune windows and less sensitivity to both ammo(rf) and atmospheric conditions.

Obviously, the person you refer to with the 21oz tuner has good ammo, good equipment, and has learned to steer the gun very well, but I don't think the heavy tuner and 4 out of his last 7 ara cards(IIRC) being 2500's, is a coincidence. It's absolutely amazing, though..and I don't think that's ever been done before. He's also relatively new to the game and builds his own rifles. Go figure! A certain prominent smith has yet to recognize this accomplishment, that I've seen. Interesting, eh? ;)

Pete Wass
03-10-2015, 02:07 PM
Pete, I've tested different weight tuners quite a bit. Soon, I hope to have vibration analysis completed. This is one that we have not yet tested. IME, more weight does give what you are seeing...wider tune windows and less sensitivity to both ammo(rf) and atmospheric conditions.

Obviously, the person you refer to with the 21oz tuner has good ammo, good equipment, and has learned to steer the gun very well, but I don't think the heavy tuner and 4 out of his last 7 ara cards(IIRC) being 2500's, is a coincidence. It's absolutely amazing, though..and I don't think that's ever been done before. He's also relatively new to the game and builds his own rifles. Go figure! A certain prominent smith has yet to recognize this accomplishment, that I've seen. Interesting, eh? ;)

It is indeed a remarkable accomplishment. Talk about outside the box, eh? I don't know if you know of or have seen Denny A's rifle with 37 Lbs. of tuner? Really outside the box!

Pete

mks
03-10-2015, 05:46 PM
He is using a tuner that is nearly three times heavier than most others use.

Is this monster tuner beyond the muzzle or not?

Thanks,
Keith

Pete Wass
03-10-2015, 07:44 PM
Is this monster tuner beyond the muzzle or not?

Thanks,
Keith

Haven't seen a picture or the rifle.

Pete

Jerry H
03-10-2015, 08:35 PM
Here is a 20+ounce tuner that I will use this year.

15962

15963

tim in tx
03-10-2015, 08:39 PM
Some assumptions must be accepted to what I am about to say. On a thread on another forum a lad who has been winning indoor rim fire matches with big scores; some of them perfect scores, describes his rifle's components. He is using a tuner that is nearly three times heavier than most others use. The assumptions being that a rifle shot is a rifle shot, regardless of caliber and powder charge and that a rifle barrel is a rifle barrel.

What I find interesting is the tuner weight. While I have been able to tune 21.5" 30 caliber barrels with 3 or 4 ounces, those seem to be finicky, from my experience. Not all the time but under some conditions. While it is probably impossible for CF folks to use 30 or 40 oz to tune a barrel, I am wondering if anyone has ever gone in that direction? More in line with "Positive Compensation" perhaps?

Thanks,

Pete

with all weight being added in front of the crown 1 ounce at a time up to 30 ounces, At 100yds ,essentually I map the vertical movements of the barrel on target. I start with 2 loads averaging 45 fps apart or 1 grain of powder charge,shoot 1 shot of each powder charge at the same spot,note the vertical,move sideways on the target 1 inch and add another ounce and repeat the 2 shots untill I have added the limit of weight which is generally 30 ounces.Then put together a map of the 2 shot groups side by side in order of adding weight and end up with a complete map of barrel movements on paper. Once I have picked the weight which looks the best and fine tuned it to be dead level and will making no further adjustments of the tuner. Then what I do is check the width of tune or velocites corrected by shooting 1 group with 5 grains of powder differences within that group at 100 yds,I start with the middle powder charge first to get a hole established,then shoot a 1 grain less and keep going to the point of dropping out the bottom that being the limit for the slow end and then I go the other direction on powder changes ,when the fastest one pop out the top that would be the upper limit,then I know my width of tune..I am sure you guys know how much temp effects velocities so what I am looking for is a velocity range that is equal or wider then the changes incurred by temp changes with a single load with 20 degrees to 105 degrees of temp change. I am guessing it would be aprox 100 fps change through the range of temps.After all of this at 100yds then I re adjust for 1000 yds which is usually just a couple of clicks away from the 100 yd tune.

Tim in Tx

tim in tx
03-10-2015, 08:50 PM
Here is a 20+ounce tuner that I will use this year.

15962

15963

Thats a good looking ,big ol tuner right there.


Tim in Tx

JerrySharrett
03-10-2015, 09:01 PM
Here is a 20+ounce tuner that I will use this year.



Now, boy howdy, that is a tuner!! Rimfire or centerfire?

Be interesting to see how sensitive this monster is.

On my 10 oz Fudds a 0.007" axial movement would take me from dot to dash or dot to vertical.

.

Pete Wass
03-10-2015, 09:16 PM
Now, boy howdy, that is a tuner!! Rimfire or centerfire?

Be interesting to see how sensitive this monster is.

On my 10 oz Fudds a 0.007" axial movement would take me from dot to dash or dot to vertical.

.

on a 40X RF rifle. It was bored big enough so that it would slide behind the muzzle. I tried it both hanging over the muzzle and all of it behind the muzzle and the rifle shot the same, either way it was located. I use to keep it behind the muzzle so that I didn't have to clean it. This was back in the 90's sometime.

Pete

Jerry H
03-10-2015, 09:38 PM
I went over to the dark side (RF) when I quit CF several years ago. This is a RF. This is actually a dual tuner. The main body scale is toward the barrel. The 1.5 ounce second tuner is at the exit end.

Pete Wass
03-10-2015, 10:17 PM
is an interesting concept, using that light ring @ the rear of it, which apparently does change the tune of it. It's interesting to know that going from being what we consider "in tune" at, say, 8 oz to 20 or even 30 oz may be an improvement. I am guessing there must be other nodes between those weights where "tune" seems to appear? It appears that a lot more weight than is customary may be "better", eh?

Pete

Pete Wass
03-10-2015, 10:23 PM
I think I have determined that bloop tube type tuners are only effective because of their weight AND tune changes from day to day with them. With the rifles I have, a mid-barrel sliding weight seems to provide the most stable tune for them. ( A rifle shot is a rifle shot concept again) Have youse guys done any testing with mid-barrel tuners?

Pete

Boyd Allen
03-11-2015, 12:05 AM
Tim,
Great post....thanks for all the info.
Boyd

JerrySharrett
03-11-2015, 06:17 AM
I went over to the dark side (RF) when I quit CF several years ago. This is a RF. This is actually a dual tuner. The main body scale is toward the barrel. The 1.5 ounce second tuner is at the exit end.

So this device will make a sows purse into a silk ear? And, will make Federal Lightening onto Eley 10X?

Jerry H
03-11-2015, 08:00 AM
Not hardly! Even the high dollar ammo leaves a lot to be desired for the price. But then again, I judge it by how well it shoots a 40 shot group. Anything under .550 moa is a good lot. Sometimes I wonder what a CF would with a 40 shot group test. Maybe not much better.

Pete Wass
03-11-2015, 11:56 AM
says that there is .150" of vertical built into our best ammo. Be that true, taking that out is the quest. From new developments, things look more promising, I must say.

Pete

mwezell
03-11-2015, 12:37 PM
says that there is .150" of vertical built into our best ammo. Be that true, taking that out is the quest. From new developments, things look more promising, I must say.

Pete
I'll just point out to those that may be thinking otherwise, Pete's post is in reference to rimfire ammo, I believe.

Pete Wass
03-11-2015, 01:30 PM
I'll just point out to those that may be thinking otherwise, Pete's post is in reference to rimfire ammo, I believe.

I should have stated that. If we had that much vertical built into our CF ammo, we would be a lot more frustrated, eh?

Pete

Pete Wass
03-11-2015, 07:48 PM
I doubt it's "built in". I believe it's considered "acceptable".
It's just a matter of terminology.

I can't imagine anyone accepting much, if any, vertical. I'm pretty sure he says built in. The problems cones in very few rounds. Sometimes a whole box will be ok , but rarely, from my experience. I always hope the bad ones go into the sighter.

Pete