Feedback From The Tunnel
- Thread starter Gene Beggs
- Start date
mwezell
Mike Ezell
Thank you Gene!
mwezell
Mike Ezell
Richard, I hope you don't leave. I just think that the details of WHY they work are, at best, debatable in several aspects. There are people like Keith that can explain a lot of it, but yet there are things obviously missing that are verifiable in use. I mean zero disrespect in that statement...I wish I was as smart and as educated as he is. From what I can tell, and I've spoken with some VERY qualified individuals....there are too many variables to be accounted for, all happening in small fractions of time, that are not always identical.
Makes for a tough equation for even the best of the best that the USA has to offer.
That said, we've come a long, long way and you are a part of that.
I think the greater good is in how to use tuners rather than theorizing and Internet speculation about how they do what they do. One is very simple and the other is just the opposite. Jm2c.
jimmymac
J McGregor
Count me in as one of the 5000. I don't need to be in the weeds with this, but I'm glad that folks like you, Richard, etc are interested in it.
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M
mks
Guest
Mike,
Stiffness, the inverse of which is a measure of how far the barrel deflects with a given force (F= k*x where F is force and x is deflection), is k = E*D^4/L^3 (the same formula as for frequency except without the square root). So your hypothetical barrel with 10X more deflection has 1/10th the stiffness. Speed is amplitude times frequency, so speed = frequency/k, which gives [L^3/(E*D^4)]^(1/2).
I haven't tested a lot of stocks, but it may be safe to say that most stocks are less stiff than barrels. The barrel and forend are like a tuning fork with one side stiffer than the other. The less stiff side tends to have greater deflection, so the forend and where it is supported on the rest is important for compensation.
Keith
M
mks
Guest
One thing I question about tuners is how much we really know about how to adjust them for temperature and other factors. If we base tuner adjustment on, say, two three-shot groups, statistical significance is pretty low. The conclusions we draw about which setting is best have a good chance of being wrong. I don't get to do a lot of testing, but from what I have done, even two ten-shot groups is not fool proof. One typical test gave 75% confidence comparing two five-shot groups at each setting. That is decent confidence, but the scientific community generally takes 95% confidence as the threshold for statistical significance.
American Rifleman requires five five-shot groups in their articles, which may be about right for drawing strong conclusions. 50 shots (!!!) to know for sure if one setting is better than another. That is not something that can be done during a match.
Landy has used good statistical techniques to study 22RF accuracy. Has anyone applied analysis of variance (ANOVA) to centerfire tuners? My testing is limited to two different temperatures. I interpolate for other temperatures. What needs to be done is more groups at more temperatures until 95% confidence is reached. Any volunteers? ;^)
American Rifleman requires five five-shot groups in their articles, which may be about right for drawing strong conclusions. 50 shots (!!!) to know for sure if one setting is better than another. That is not something that can be done during a match.
Landy has used good statistical techniques to study 22RF accuracy. Has anyone applied analysis of variance (ANOVA) to centerfire tuners? My testing is limited to two different temperatures. I interpolate for other temperatures. What needs to be done is more groups at more temperatures until 95% confidence is reached. Any volunteers? ;^)
M
mks
Guest
Mike,
I remember that you shoot a lot of sighters. If, during a match, you suspect that an adjustment may be needed, how many shots do you base this opinion on? Say, three shot group over 0.XX? And once you make an adjustment, how many shots do you use to confirm that the adjustment worked? Say, three-shot group under 0.YY? You can see where I am going with this ...
Not trying to pick a fight, because I probably currently do the same as you. I base the quality of my adjustments on too few shots to have statistical confidence. After a good adjustment, one can shoot a 0.4" group, and after a bad adjustment, a 0.2" group. The statistics eventually win out, but you don't find out until you have shot enough groups that the match is over.
Keith
I remember that you shoot a lot of sighters. If, during a match, you suspect that an adjustment may be needed, how many shots do you base this opinion on? Say, three shot group over 0.XX? And once you make an adjustment, how many shots do you use to confirm that the adjustment worked? Say, three-shot group under 0.YY? You can see where I am going with this ...
Not trying to pick a fight, because I probably currently do the same as you. I base the quality of my adjustments on too few shots to have statistical confidence. After a good adjustment, one can shoot a 0.4" group, and after a bad adjustment, a 0.2" group. The statistics eventually win out, but you don't find out until you have shot enough groups that the match is over.
Keith
mwezell
Mike Ezell
Keith, I shoot a lot of sighters to verify the flags and sighter are in agreement. Sometimes I run and sometimes I pick. I don't shoot nearly the same number of sighters when running a target.
I've already explained how I tune. It's usually done on the warm up, hopefully, in good conditions. I fire a fouler, then a 2 or three shot group on the sighter. It's usually clear that its either in tune or its not. I make an adjustment based on group size and shape. If it looks good, I likely fire another group to verify. If it's only close I make a small adjustment...it either gets better or worse and I adjust accordingly. Adjustments are clear unless conditions are bad. It's really even easier than this sounds. We should get together and I'll show you exactly what I look for, but I posted a pic early in this thread that shows it pretty well. It's never more than a mark or two out unless I've had the tuner off or something is wrong. The only exception to that is last year when I was trying to tune a gun that I was not very familiar with, at 300 yards, right before a tornado and hail storm blew through. That's a tough condition to replicate but it was about 3 marks out. So yes, in this context, more shots are a much better. It was the first and only time I felt a little lost with a tuner. On top of everything, I got the gun home and found a problem that kept the gun from shooting as well as it should've been. So, I was chasing my tail and it may or may not have had anything to do with tune, per se. Lots of variables that day.
While my and others findings may not agree with your calculations, it's clear as day and dark, Keith.
In my limited experience, a three shot group during a match will usually tell you what you need to know. Three shots in a tiny hole tells me I can shoot that card. If I get one out of the group, I might want to make an adjustment or at least shoot another group. Of course, one has to have some wind reading skills to make this work. If you are dealing with mirage and switchy wind at the same time (not unusual) you could have a problem understanding what the rifle is saying. Truthfully, I rarely make adjustments during a match. The exception might be an extreme temperature change. Having a tuner that creates a wide tune window helps. Of course being a score shooter, as Jerry points out, I don't really need a very accurate rifle to begin with.
Rick
mwezell
Mike Ezell
But apparently, you have one. Congrats on your win yesterday!
Gene Beggs
Active member
Wrapping It Up
Well guys, we've pretty well discussed this thing to death so it's time for a few reminders and recommendations about loading your cartridges and to the range we go!
Remember that you must change NOTHING but tuner setting when using a tuner. If you are one that just has to constantly change powder, charge weight, bullets, seating depth, neck tension etc., maybe it would be better if you stay away from tuners because you will surely drive yourself crazy by chasing your tail. But if you're willing to listen and give it an honest try, you are in for a pleasant surprise!
Any experienced benchrester has a pet load. A 'go-to' combination that can usually be counted on to pull him out of the ditch when he's having trouble. So lets say your pet load is;
1. 28.8 grains of Vit.,N133 powder. Set your powder dispenser with a scale and lock that sucker down and don't touch it again!
2. A 64 to 68 grain bullet that has proven itself in competition. Flat base or boat tail, I don't think it matters in short range group shooting. There are many fine 6mm BR bullets available, pick one. Let's say for example you have a good supply of Berger Columns and they have always shot well in your rifle. Use the neck tension that feels right to you and seat the bullets 'just-off-the-lands.' Yep, just off! As close to the lands as you can get them without sticking in the leade. It's better to have the bullets jumping .005 or even .010 rather than seated any amount into the lands. You don't have to believe me; just try it! I think you'll be pleasantly surprised and it eliminates any thought about changing seating depth.
3. Primer of your choice. I use Wolf SRM.
"Alright Beggs, I've got twenty good Lapua cases loaded as you say and my tuner is set to 'zero." "Now you're tellin' me that I can go to the line and get my rifle in tune by moving only the tuner no more than three or four thousandths (three or four marks) during the warmup and KEEP it in tune throughout the day with only slight tuner adjustments?"
"Yeah, right Beggs, I'll believe that when I see it."
I'm serious as I can be and you will not believe how easy it is but you must be willing to leave your load EXACTLY the same, making adjustments with only the tuner. Ready??? Okay, here we go!
MATCH ONE.
Temp 60 degrees, clean barrel and rifle settled into the bags. Tuner set to zero.
Range officer says, "You will have ten minutes to complete your firing. Place bolts in rifles, commence firing."
After glancing down the bore to be sure it's clear, insert the bolt, chamber a round and fire a fouling shot on the sighter, holding at your pet spot just to be sure the rifle is on paper. Fire a second shot with a careful hold where you prefer, (I center the dot in the ten ring.) If you're reasonably satisfied with where the rifle is printing, it's time to fire a three shot test group. If you feel a scope adjustment is necessary, go ahead and make it and fire a couple of sighters to be sure it's where you want it and to settle the scope in. Now we're ready to check to see if the rifle is in tune.
You have about a one in four chance of being right in tune with the tuner set to 'zero,' but I'm rarely that lucky so let's say the three shot test group prints slightly under point of aim and slightly right due to a left to right crosswind .It doesn't look too bad but certainly not what you want. There is about two bullet holes of vertical and more horizontal than the wind would suggest. So let's make a one mark adjustment of the tuner. Which way? Either way is fine we are just looking for a change. If the next test group gets worse we know we went the wrong way so go back to zero and make a one mark adjustment in the other direction. The next test group is half the size of the first with no more than one bullet hole of vertical so we make another one mark adjustment in the same direction and lo and behold, the next test group shoots a dot! That's what we want! Now we are ready to go to the record, concentrate on wind flags and shoot the winning group for match one. Make a note of temp (60 degrees) and tuner setting. (two marks out from zero) See how easy that is? !
Ten minutes have expired and the range officer says, "Cease fire, cease fire, remove your bolts, clear the benches."
So we clear our equipment from the bench and return to the loading area to clean, reload cases, discuss strategy etc.
" Do we have to clean the rifle after each match?" you ask. In my opinion, no. I usually finish a five match yardage before cleaning but many insist on cleaning after each relay. I don't think it really matters with good barrels that are not prone to fouling. If the barrel is already fouled when we get back to the line, we will have an advantage over those that clean every time in that we can go right to the record if we happen to have a perfect condition when the range officer says, "Commence firing." We won't have to shoot foulers and can 'machine gun' a group before conditions change.
So we have only six loaded rounds of our original twenty so we will reload the fourteen empties with exactly the same load as used in match one. Since there will be three more relays that must shoot before we are called back to the line for match two, we have some time to relax, have a cup of coffee and observe conditions.
MATCH TWO
Once relay three has cleared the benches the range officer calls, "Relay one, shooters to the line."
As we approach the firing line, we notice that temperature has increased by ten degrees and is now showing 70 F.
"So" you ask, "should we have made an adjustment to the powder charge to compensate for the increase in temp?"
NO, absolutely not! Remember, we will make adjustments for atmospheric changes only with the tuner.
"Okay, then should we make a tuner adjustment to compensate for a temp increase of ten degrees?" you ask?
Maybe, but probably not. This is a new rifle and the tuner installed is an Ezell PDT. Turning the tuner 'out' decreases barrel vibration frequency and 'in' toward the breach increases it. As the air warms and thins out, the bullets encounter less atmospheric resistance as they accelerate down the bore and may begin to exit the muzzle before it reaches its optimum position for bullet release. Will the ten degree increase in temp be enough to make a difference on the target? Only one way to be sure. That's right, fire a test group on the sighter.
The left crosswind has increased and the test group shows more horizontal than vertical. Is the temp increase worth making a small tuner adjustment to compensate for vertical? Not in my opinion. So lets leave the tuner alone and concentrate on the the wind flag tails to minimize horizontal and shoot the record group.
The record group shows almost no horizontal and only a bullet hole of vertical and measures a nice .150, so we made a good decision and remain near the top of the leader board. Okay, so far, so good. Back to the loading area before match 3.
Should we clean? Not necessarily, but if it'll make you feel better; sure, go ahead.
MATCH THREE
The range officer announces, relay one shooters to the line.
We are loaded and clean. After bench setup we notice the winds are now from right to left and temp has increased to 80 degrees. We can be sure that with an increase of 20 degrees and shooting N133, we will have to make a tuner adjustment to compensate for the thinner air. How much? Which way?
Remember that as the air warms and thins out, the bullets encounter less atmospheric resistance as they accelerate down the bore reducing the in-bore time which results in the bullets exiting early before the muzzle has reached its optimum position during its upswing. So, to prevent an increase in vertical dispersion, we must speed up the barrel a bit to maintain optimal bullet exit timing. We do this by turning the tuner 'in' toward the breach a bit which raises the barrel vibration frequency. How much? Start with one mark. It is unlikely it will take more than one; maybe two at the most.
Do all tuners work the same? No, not all but the Ezell PDT tuner which we are using, raises the frequency when turned in toward the breach and lowers frequency when turned out toward the muzzle. It's as simple as focusing the image sharpness on a projector lense.
If the rifle has gone out of tune a bit due to thinner air, you can be sure it will require an adjustment 'in' toward the breach which raises the barrel vibration frequency. Simple; huh?
By the time we optimize tune on the sighter, winds have shifted back from left to right and increased in velocity. Three minutes remain for us to shoot our record group. Should we wait for the wind to slow and reverse direction as it has been doing lately or go ahead and risk shooting in the pick up? We have plenty of time, so let's wait. The range officer announces, 'two minutes, you have two minutes to complete your firing.' Wind velocity is definitely decreasing and as the range officer announces 'one minute left to complete your firing', wind direction changes back from right to left with very light velocity. Go for it! Five record shots as quickly as you can shoot and still retain accurate aim and good rifle handling.
Cease fire, cease fire, remove your bolts, clear the benches. We made a good decision. The third group measures a nice .160 moving us to the top of the leader board!
Well, what do you think? Pretty neat; huh? Isn't tuning with a tuner easier than carrying three different loads to the line or pulling bullets on rounds that are loaded too hot and/or changing bullet seating depth? With a tuner, we can make quick, easy adjustments at the line as long as we remove the bolt and remain seated. You can't beat it!
To be continued with match 4 and 5. Lets take a break.
GB
Well guys, we've pretty well discussed this thing to death so it's time for a few reminders and recommendations about loading your cartridges and to the range we go!
Remember that you must change NOTHING but tuner setting when using a tuner. If you are one that just has to constantly change powder, charge weight, bullets, seating depth, neck tension etc., maybe it would be better if you stay away from tuners because you will surely drive yourself crazy by chasing your tail. But if you're willing to listen and give it an honest try, you are in for a pleasant surprise!
Any experienced benchrester has a pet load. A 'go-to' combination that can usually be counted on to pull him out of the ditch when he's having trouble. So lets say your pet load is;
1. 28.8 grains of Vit.,N133 powder. Set your powder dispenser with a scale and lock that sucker down and don't touch it again!
2. A 64 to 68 grain bullet that has proven itself in competition. Flat base or boat tail, I don't think it matters in short range group shooting. There are many fine 6mm BR bullets available, pick one. Let's say for example you have a good supply of Berger Columns and they have always shot well in your rifle. Use the neck tension that feels right to you and seat the bullets 'just-off-the-lands.' Yep, just off! As close to the lands as you can get them without sticking in the leade. It's better to have the bullets jumping .005 or even .010 rather than seated any amount into the lands. You don't have to believe me; just try it! I think you'll be pleasantly surprised and it eliminates any thought about changing seating depth.
3. Primer of your choice. I use Wolf SRM.
"Alright Beggs, I've got twenty good Lapua cases loaded as you say and my tuner is set to 'zero." "Now you're tellin' me that I can go to the line and get my rifle in tune by moving only the tuner no more than three or four thousandths (three or four marks) during the warmup and KEEP it in tune throughout the day with only slight tuner adjustments?"
"Yeah, right Beggs, I'll believe that when I see it."
I'm serious as I can be and you will not believe how easy it is but you must be willing to leave your load EXACTLY the same, making adjustments with only the tuner. Ready??? Okay, here we go!
MATCH ONE.
Temp 60 degrees, clean barrel and rifle settled into the bags. Tuner set to zero.
Range officer says, "You will have ten minutes to complete your firing. Place bolts in rifles, commence firing."
After glancing down the bore to be sure it's clear, insert the bolt, chamber a round and fire a fouling shot on the sighter, holding at your pet spot just to be sure the rifle is on paper. Fire a second shot with a careful hold where you prefer, (I center the dot in the ten ring.) If you're reasonably satisfied with where the rifle is printing, it's time to fire a three shot test group. If you feel a scope adjustment is necessary, go ahead and make it and fire a couple of sighters to be sure it's where you want it and to settle the scope in. Now we're ready to check to see if the rifle is in tune.
You have about a one in four chance of being right in tune with the tuner set to 'zero,' but I'm rarely that lucky so let's say the three shot test group prints slightly under point of aim and slightly right due to a left to right crosswind .It doesn't look too bad but certainly not what you want. There is about two bullet holes of vertical and more horizontal than the wind would suggest. So let's make a one mark adjustment of the tuner. Which way? Either way is fine we are just looking for a change. If the next test group gets worse we know we went the wrong way so go back to zero and make a one mark adjustment in the other direction. The next test group is half the size of the first with no more than one bullet hole of vertical so we make another one mark adjustment in the same direction and lo and behold, the next test group shoots a dot! That's what we want! Now we are ready to go to the record, concentrate on wind flags and shoot the winning group for match one. Make a note of temp (60 degrees) and tuner setting. (two marks out from zero) See how easy that is? !
Ten minutes have expired and the range officer says, "Cease fire, cease fire, remove your bolts, clear the benches."
So we clear our equipment from the bench and return to the loading area to clean, reload cases, discuss strategy etc.
" Do we have to clean the rifle after each match?" you ask. In my opinion, no. I usually finish a five match yardage before cleaning but many insist on cleaning after each relay. I don't think it really matters with good barrels that are not prone to fouling. If the barrel is already fouled when we get back to the line, we will have an advantage over those that clean every time in that we can go right to the record if we happen to have a perfect condition when the range officer says, "Commence firing." We won't have to shoot foulers and can 'machine gun' a group before conditions change.
So we have only six loaded rounds of our original twenty so we will reload the fourteen empties with exactly the same load as used in match one. Since there will be three more relays that must shoot before we are called back to the line for match two, we have some time to relax, have a cup of coffee and observe conditions.
MATCH TWO
Once relay three has cleared the benches the range officer calls, "Relay one, shooters to the line."
As we approach the firing line, we notice that temperature has increased by ten degrees and is now showing 70 F.
"So" you ask, "should we have made an adjustment to the powder charge to compensate for the increase in temp?"
NO, absolutely not! Remember, we will make adjustments for atmospheric changes only with the tuner.
"Okay, then should we make a tuner adjustment to compensate for a temp increase of ten degrees?" you ask?
Maybe, but probably not. This is a new rifle and the tuner installed is an Ezell PDT. Turning the tuner 'out' decreases barrel vibration frequency and 'in' toward the breach increases it. As the air warms and thins out, the bullets encounter less atmospheric resistance as they accelerate down the bore and may begin to exit the muzzle before it reaches its optimum position for bullet release. Will the ten degree increase in temp be enough to make a difference on the target? Only one way to be sure. That's right, fire a test group on the sighter.
The left crosswind has increased and the test group shows more horizontal than vertical. Is the temp increase worth making a small tuner adjustment to compensate for vertical? Not in my opinion. So lets leave the tuner alone and concentrate on the the wind flag tails to minimize horizontal and shoot the record group.
The record group shows almost no horizontal and only a bullet hole of vertical and measures a nice .150, so we made a good decision and remain near the top of the leader board. Okay, so far, so good. Back to the loading area before match 3.
Should we clean? Not necessarily, but if it'll make you feel better; sure, go ahead.
MATCH THREE
The range officer announces, relay one shooters to the line.
We are loaded and clean. After bench setup we notice the winds are now from right to left and temp has increased to 80 degrees. We can be sure that with an increase of 20 degrees and shooting N133, we will have to make a tuner adjustment to compensate for the thinner air. How much? Which way?
Remember that as the air warms and thins out, the bullets encounter less atmospheric resistance as they accelerate down the bore reducing the in-bore time which results in the bullets exiting early before the muzzle has reached its optimum position during its upswing. So, to prevent an increase in vertical dispersion, we must speed up the barrel a bit to maintain optimal bullet exit timing. We do this by turning the tuner 'in' toward the breach a bit which raises the barrel vibration frequency. How much? Start with one mark. It is unlikely it will take more than one; maybe two at the most.
Do all tuners work the same? No, not all but the Ezell PDT tuner which we are using, raises the frequency when turned in toward the breach and lowers frequency when turned out toward the muzzle. It's as simple as focusing the image sharpness on a projector lense.
If the rifle has gone out of tune a bit due to thinner air, you can be sure it will require an adjustment 'in' toward the breach which raises the barrel vibration frequency. Simple; huh?
By the time we optimize tune on the sighter, winds have shifted back from left to right and increased in velocity. Three minutes remain for us to shoot our record group. Should we wait for the wind to slow and reverse direction as it has been doing lately or go ahead and risk shooting in the pick up? We have plenty of time, so let's wait. The range officer announces, 'two minutes, you have two minutes to complete your firing.' Wind velocity is definitely decreasing and as the range officer announces 'one minute left to complete your firing', wind direction changes back from right to left with very light velocity. Go for it! Five record shots as quickly as you can shoot and still retain accurate aim and good rifle handling.
Cease fire, cease fire, remove your bolts, clear the benches. We made a good decision. The third group measures a nice .160 moving us to the top of the leader board!
Well, what do you think? Pretty neat; huh? Isn't tuning with a tuner easier than carrying three different loads to the line or pulling bullets on rounds that are loaded too hot and/or changing bullet seating depth? With a tuner, we can make quick, easy adjustments at the line as long as we remove the bolt and remain seated. You can't beat it!
To be continued with match 4 and 5. Lets take a break.
GB
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Hunter
Chasin' the Sunset
That sounds basically like your previous instructions for tuning with powder changes -- so, what does the tuner do that powder-tuning doesn't?
Gene Beggs
Active member
JerrySharrett
Senile Member
Bill, if you have a barrel that is not in its optimum tune,and, the tuner is heavy enough, the tuner CAN be used to put it in its optimum tune. If the barrel is not in its optimum tune and the tuner is not heavy enough you can use that light weight tuner to partially tune the barrel. Either way if that barrel is not in its optimum you can use the tuner to improve that barrels accuracy...set and forget.
OR, you can use the tuner as an additional tuning component.
.
mwezell
Mike Ezell
I was nodding my head, yes..until the last statement.
Once I find my max load, I back down to the next or even second one down, then never change the load again. I keep it in tune by just nudging the tuner a mark or two.
That's part of the beauty of a tuner. You can tweak the last ounce out of a given load, in good conditions...and do it at the bench.
Gene
Thank you for the great information on tunner's!
Since were in between matches at the moment. If you have time for a quick question? the following two comments..
"Any experienced benchrester has a pet load. A 'go-to' combination that can usually be counted on to pull him out of the ditch when he's having trouble."
" Set your powder dispenser with a scale and lock that sucker down and don't touch it again!"
I'm curious If you have tried preloading lets say 40-50 rds and sat down at your bench in the tunnel and shot let say 10rds this week 10rds the week after etc-etc-etc. To see what your results would be!
Thanks again
Russ
Thank you for the great information on tunner's!
Since were in between matches at the moment. If you have time for a quick question? the following two comments..
"Any experienced benchrester has a pet load. A 'go-to' combination that can usually be counted on to pull him out of the ditch when he's having trouble."
" Set your powder dispenser with a scale and lock that sucker down and don't touch it again!"
I'm curious If you have tried preloading lets say 40-50 rds and sat down at your bench in the tunnel and shot let say 10rds this week 10rds the week after etc-etc-etc. To see what your results would be!
Thanks again
Russ