mwezell
Mike Ezell
Gene, we can agree to disagree about something that doesn't seem to matter, but science is on my side in this one.
mwezell
Mike Ezell
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.
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mwezell
Mike Ezell
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
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
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SCOTTY CRAWFORD
New member
Tuner Cover?????????
Mike,
Where is the pic of the tuner with the tuner cover installed??? Inside joke you had to be there!
Mike,
Where is the pic of the tuner with the tuner cover installed??? Inside joke you had to be there!
mike
"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, 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
New member
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.
Gene, I think you need to abandon all of your match proven ideas and start all over, especially before this years Crawfish.
mwezell
Mike Ezell
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
Mike Ezell
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.
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.
jackie schmidt
New member
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.
Your welcome. Sarcasm noted.
JerrySharrett
Senile Member
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.
.
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
New member
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
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
Attachments
jackie schmidt
New member
Attachments
Boyd Allen
Active member
Thanks Jackie,
That post was a jewel of solid information.
Boyd
That post was a jewel of solid information.
Boyd
mwezell
Mike Ezell
Yes it was. Thank you Jackie.
M
mks
Guest
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.
F
Fretka
Guest
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!
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!
M
mks
Guest
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
Mike Ezell
Alright, so more amplitude is good, and tuners give more amplitude, right?
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?
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
Active member
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.
M
mks
Guest
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