Feedback From The Tunnel

Gene,
Thanks for initiating a tuner thread. I am late to the party, but would like to offer some thoughts. I agree with you and Mike that tuning a tuner is simple if you don't worry about how it works. One is never more than a few marks away from tune. If you are not satisfied with the tune, shoot some groups at different tuner settings, and voila, you know which setting is best.

But how does one know how often to do such testing, in anticipation that tune has changed? The math says that Youngs modulus of the barrel drops by about 4.9 ksi per degree F, and the barrel expands in all directions by 5.5E-6 inches per inch per degree F. The decrease in Youngs modulus decreases stiffness and natural frequency, but the barrel expansion increases it. The net effect for a 22" barrel is that the tuner needs to move toward the breech by a little over 0.001" per degree F to keep the same natural frequency, i.e., to keep the barrel vibrating the same. Further movement toward the breech is needed to compensate for the increase in bullet velocity as temperature increases.

I can't say that I have done enough testing to confirm how best to chase tune as the day warms up. But until I do, I move the tuner before almost every relay to try to stay in the ball park, and tend to think I that I may not be adjusting enough. I know Mike sometimes doesn't move his tuner all day. Just wondering your thoughts on this and whether tune versus temperature is something you can test in the tunnel.

I welcome Mike and anyone else to offer their experience, as well. I don't mean to sabotage your thread, hope it is OK with you.

Best,
Keith
 
Gene,
Thanks for initiating a tuner thread. I am late to the party, but would like to offer some thoughts. I agree with you and Mike that tuning a tuner is simple if you don't worry about how it works. One is never more than a few marks away from tune. If you are not satisfied with the tune, shoot some groups at different tuner settings, and voila, you know which setting is best.

But how does one know how often to do such testing, in anticipation that tune has changed? The math says that Youngs modulus of the barrel drops by about 4.9 ksi per degree F, and the barrel expands in all directions by 5.5E-6 inches per inch per degree F. The decrease in Youngs modulus decreases stiffness and natural frequency, but the barrel expansion increases it. The net effect for a 22" barrel is that the tuner needs to move toward the breech by a little over 0.001" per degree F to keep the same natural frequency, i.e., to keep the barrel vibrating the same. Further movement toward the breech is needed to compensate for the increase in bullet velocity as temperature increases.

I can't say that I have done enough testing to confirm how best to chase tune as the day warms up. But until I do, I move the tuner before almost every relay to try to stay in the ball park, and tend to think I that I may not be adjusting enough. I know Mike sometimes doesn't move his tuner all day. Just wondering your thoughts on this and whether tune versus temperature is something you can test in the tunnel.

I welcome Mike and anyone else to offer their experience, as well. I don't mean to sabotage your thread, hope it is OK with you.

Best,
Keith

Good post Keith and glad you're here.

All I can say is, there has to be more to it. I can promise you that if I moved my tuner as you just described, I would not be happy at the end of the day and likely not again after the initial setting and target.

Off the top of my head, how about just having the mass at the end of the barrel and it's effect?
I know that on the barrels tested, my tuner lowered the frequency and increased initial muzzle deflection. Frequency was affected about 3.5 times as much as deflection.
 
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Keith, I don't know

all the science behind this tuner stuff but you are right on the money with what I have seen over several years of testing and shooting matches and getting the same results as you.

I ran a "ahead of the crown" tuner for probably three years and ended up doing just what you are talking about. In big temp swings or days where there was no wind and the bbl just wanted to stay warm it was a huge issue keeping the rifle in tune. I got where I could anticipate how much to turn the tuner in before the next relay and be pretty well right on the tune. At some matches the tuner would be in .010 by the end of the day. It worked very well doing that and won a lot of 2-guns doing that.
I have a test that you ought to try. Take a "ahead of the crown" tuner and get the gun tuned on a cool bbl, now get a heat gun and warm the bbl and shoot again and see what happens.
Do the same with a "behind the crown" tuner. I would like to hear your results and see if they mirror my testing. I have literally shot thousands of rounds and wore out more bbl.'s than I would care to count just testing different tuner designs and finding what works the best under adverse conditions. I have had several top shooters out to my range walk away amazed at what a tuner can do for you or to you if you don't have a handle on the little quirks that different tuner designs have.

Richard
 
all the science behind this tuner stuff but you are right on the money with what I have seen over several years of testing and shooting matches and getting the same results as you.

I ran a "ahead of the crown" tuner for probably three years and ended up doing just what you are talking about. In big temp swings or days where there was no wind and the bbl just wanted to stay warm it was a huge issue keeping the rifle in tune. I got where I could anticipate how much to turn the tuner in before the next relay and be pretty well right on the tune. At some matches the tuner would be in .010 by the end of the day. It worked very well doing that and won a lot of 2-guns doing that.
I have a test that you ought to try. Take a "ahead of the crown" tuner and get the gun tuned on a cool bbl, now get a heat gun and warm the bbl and shoot again and see what happens.
Do the same with a "behind the crown" tuner. I would like to hear your results and see if they mirror my testing. I have literally shot thousands of rounds and wore out more bbl.'s than I would care to count just testing different tuner designs and finding what works the best under adverse conditions. I have had several top shooters out to my range walk away amazed at what a tuner can do for you or to you if you don't have a handle on the little quirks that different tuner designs have.

I

Richard

I know I'd like to hear more about these test results. I'm just about ready to buy a tuner. Thanks.
 
Jim,

shoot me an e-mail. I don't want to get into "who has the best" on this forum. I have no ties to any certain tuner design but some do work better under certain conditions.
It's easy to make any design work under benign conditions, it's the unusual and adverse conditions where certain ones work better than others.

Richard
 
Welcome Aboard Keith!

Gene,
Thanks for initiating a tuner thread. I am late to the party, but would like to offer some thoughts. I agree with you and Mike that tuning a tuner is simple if you don't worry about how it works. One is never more than a few marks away from tune. If you are not satisfied with the tune, shoot some groups at different tuner settings, and voila, you know which setting is best.

But how does one know how often to do such testing, in anticipation that tune has changed? The math says that Youngs modulus of the barrel drops by about 4.9 ksi per degree F, and the barrel expands in all directions by 5.5E-6 inches per inch per degree F. The decrease in Youngs modulus decreases stiffness and natural frequency, but the barrel expansion increases it. The net effect for a 22" barrel is that the tuner needs to move toward the breech by a little over 0.001" per degree F to keep the same natural frequency, i.e., to keep the barrel vibrating the same. Further movement toward the breech is needed to compensate for the increase in bullet velocity as temperature increases.

I can't say that I have done enough testing to confirm how best to chase tune as the day warms up. But until I do, I move the tuner before almost every relay to try to stay in the ball park, and tend to think I that I may not be adjusting enough. I know Mike sometimes doesn't move his tuner all day. Just wondering your thoughts on this and whether tune versus temperature is something you can test in the tunnel.

I welcome Mike and anyone else to offer their experience, as well. I don't mean to sabotage your thread, hope it is OK with you.

Best,
Keith


Hey Keith! I'm delighted you joined us for this tuner discussion. You? Sabotage the thread? Heavens no! You are our 'go to' engineer when we need help.

Guys, I'm not going to put Keith Sharp (MKS) on the spot by telling you who and what he is but when it comes to mechanical engineering, his is the 'last word'.

Keith, you are so right when you say, "Tuning a tuner is so simple if you don't worry about how it works." That is absolutely true!

Several of us have been studying and experimenting with tuners right along during the past few years and significant progress has been made. I believe we are just about at the point where we are all in agreement and can finally say, "We've got it!!" And I put Mike Ezell at the head of the class! Richard Brensing and Rodney Brown must also be included in this threesome for the work they have done. They are all three at the cutting edge of tuner technology.

Mike Ezell is in the business (I'm not, I'm just a hobbyist ) Mike has invested a great deal of time and money developing his PDT tuner. He has poured his heart into it and knows it represents state-of-the-art in tuner technology. That's why he monitors everything said so carefully and speaks up when he sees or hears something that is contrary to what he has proven with his experiments.

I hope the benchrest community will begin showing Mike Ezell how much we appreciate what he has done for us by adopting his PDT tuner as the standard by which all others are judged. If we will all procure one of his tuners, install it per his instructions and begin using it in accordance with his recommendations we will all be on the same page so to speak. I intend to do just that and I've advised him of my intentions. Why not join us and discover what some of us have known for years and that is "Tuners Are The Answer" to getting and keeping a benchrest rifle in tune.

Later,

Gene Beggs
 
all the science behind this tuner stuff but you are right on the money with what I have seen over several years of testing and shooting matches and getting the same results as you.

I ran a "ahead of the crown" tuner for probably three years and ended up doing just what you are talking about. In big temp swings or days where there was no wind and the bbl just wanted to stay warm it was a huge issue keeping the rifle in tune. I got where I could anticipate how much to turn the tuner in before the next relay and be pretty well right on the tune. At some matches the tuner would be in .010 by the end of the day. It worked very well doing that and won a lot of 2-guns doing that.
I have a test that you ought to try. Take a "ahead of the crown" tuner and get the gun tuned on a cool bbl, now get a heat gun and warm the bbl and shoot again and see what happens.
Do the same with a "behind the crown" tuner. I would like to hear your results and see if they mirror my testing. I have literally shot thousands of rounds and wore out more bbl.'s than I would care to count just testing different tuner designs and finding what works the best under adverse conditions. I have had several top shooters out to my range walk away amazed at what a tuner can do for you or to you if you don't have a handle on the little quirks that different tuner designs have.

Richard

Richard, I respect your opinion and findings but they don't agree with mine in this regard. We've both done a metric ton of tuner testing so I'd like to hear more about this to see if I can replicate it. Seems a good way to determine what you're seeing and why.

As I said earlier, I would never move my tuner for every degree of temp change and have never seen the need to at anywhere even remotely close to that frequency.

Perhaps there is something to be learned here.
 
Reminders, Thoughts To Ponder, Things To Clear Up.

Well guys, hope you've had time to thoroughly read and think about what we've covered so far. My last post was number 49 on 02-11-18. Bet you thought that was all I had to say, but NO, we're not finished yet.

The discussion so far has been terrific and I want to say how much I appreciate all the fine input from Mike Ezell, Richard Brensing and others. We are making good progress in getting everyone in step and marching together toward our ultimate goal of getting the centerfire benchresters sold on the use of barrel tuners. There are a few of us who know just what a boon that will be. Of course, if we were selfish and cared only about beating up on our fellow competitors we would keep all this stuff hush hush. I can't speak for others but I am one who has always enjoyed sharing what I've learned in order to advance state of the art. I guess that's why I'm a teacher instead of a champion.

It must be emphasized that a tuner cannot make a bad barrel shoot! Same for bad bullets, powder, primers, cases, actions, scopes, rests, etc. All that and more must be up to the task but there are so many heartbreaking cases where a shooter has had his act together and been shooting great but the fourth match of the day went bad and the fifth was a train wreck bumping him way down the list with the also rans. Did conditions really get that bad or did the shooter just fail to make the proper adjustments to compensate for changes in atmospheric conditions ? If he made changes did he go in the right direction? More powder, less powder, in or out on seating depth, turn the tuner in or out, What?

We have all been there and it's so discouraging it makes you wonder if it's really worth continuing. When you do the same thing over and over time after time with the same results no matter what you try, it's enough to make you question your sanity; isn't it? The top shooters have their own 'tricks' to stay in tune and have spent many years searching for the answers. Of course, they want to win above all and most are not willing to share anything that might compromise their edge, and you can't blame them, that's just human nature. Benchrest is expensive and time consuming, but if we could master this thing called tune and concentrate on reading conditions and rifle handling we would stand a far better chance of finishing well in the next match; huh? Believe me, tuners are the answer!

More to come. Let's hear your questions.

Gene Beggs
 
I ran a "ahead of the crown" tuner for probably three years and ended up doing just what you are talking about. In big temp swings or days where there was no wind and the bbl just wanted to stay warm it was a huge issue keeping the rifle in tune. I got where I could anticipate how much to turn the tuner in before the next relay and be pretty well right on the tune. At some matches the tuner would be in .010 by the end of the day. It worked very well doing that and won a lot of 2-guns doing that.


Richard

I have never used a tuner but back a number of years ago I stumbled on a good lot of powder, primers and bullets and I managed some pretty decent groups at a local winter league. My understanding is that there is a larger temperature coefficient at higher temperatures.

Ken
 
Gene, You are right

about wondering about sanity at times! I'm going to give some lessons learned the hard way that can really make a difference.
Most, but not all of the time, we really don't shoot drastically different conditions during an agg. But what if you do?
Ok, the other morning was out testing at minus 3 degF, wind chill of -15. Got the gun tuned good. I waited an hour between groups because a warm front was coming my way and it was going to get to 60 deg by afternoon. Long story short with no tuner change I would have been shooting on the other side of the node with the tuner doing the opposite of what I want. Keeping track every hour it was no big deal keeping the gun tuned.
You might ask, What good is that test? Suppose you finish out the day on Sat and a big storm system moves through during the night. Do you have a clue where you need to be with the tuner? Can you make those changes at the firing line quick enough to shoot good and also know exactly where your at on the tuning node.

The reason I ask this is that sometimes a really good bbl will "fake you out" You think you have vertical when really it's hot and spitting vertical. I learned that lesson several years ago and believe me, that little tidbit has saved several 2-guns.
That's why I am so intense on you guys setting down and playing with the tuner under extreme condition changes. You typically won't have this happen very often but when you do you will glad you took the time to test.

Richard
 
I have no input but I do have a question :)

Has anyone ever taken the tuner off (or just started with it off) and tuned the barrel Olde Schoole to find out if it shoots, then put the tuner on?

I don't mean "for comparing the two"....... but to simplify the process. Seems to me that would save me heartache.
 
I have done that Al, but. I didn't tune to the max with powder because I knew I was gonna put the tuner on. It will usually tighten the group from there. I would think a fellow would have to shoot the same gun in the same discipline often to realize the benefits of a tuner. They take work and practice and good record keeping.
 
I have no input but I do have a question :)

Has anyone ever taken the tuner off (or just started with it off) and tuned the barrel Olde Schoole to find out if it shoots, then put the tuner on?

I don't mean "for comparing the two"....... but to simplify the process. Seems to me that would save me heartache.

Yes Al, and it works. It works equally well to do load development with the tuner on, too...Just don't touch the tuner until you find the load Olde Schoole.

You can simply throw a known load at the gun aND tune it with the tuner but, the tuner can only bring the potential of that load out. If the load won't shoot well at some specific condition, a tuner won't fix it completely.
 
Yes Al, and it works. It works equally well to do load development with the tuner on, too...Just don't touch the tuner until you find the load Olde Schoole.

You can simply throw a known load at the gun aND tune it with the tuner but, the tuner can only bring the potential of that load out. If the load won't shoot well at some specific condition, a tuner won't fix it completely.

So where are you centerfire guys starting with the tuner setting if you develop your load with the tuner on? Are you starting at setting 0, develop the load and then twist untill it shoots? Then chase the tune throughout the day? I ask because I know what I am looking for with rimfire and have an arbitrary number to get close with different length and profiles of barrels, but I am missing a big factor that you guys luckily can change and that is the load. Just curious to know how you all approach it. I would have to say that if I was going to do it tomorrow I would probably approach it the way Al outlines but at the limitations that Mike states, it may not be benifit of a new shooter to approach it that way.

Tad
 
So where are you centerfire guys starting with the tuner setting if you develop your load with the tuner on? Are you starting at setting 0, develop the load and then twist untill it shoots? Then chase the tune throughout the day? I ask because I know what I am looking for with rimfire and have an arbitrary number to get close with different length and profiles of barrels, but I am missing a big factor that you guys luckily can change and that is the load. Just curious to know how you all approach it. I would have to say that if I was going to do it tomorrow I would probably approach it the way Al outlines but at the limitations that Mike states, it may not be benifit of a new shooter to approach it that way.

Tad

There are a host of known loads that work well in the commonly used cartridges in SR BR. For example if a 6ppc won't shoot with 27.2 of LT31 and a light jamb on the bullet, then it likely won't shoot. There are also know loads with old school T32, N133 etc. As a general rule adjust the tuner to get rid of vertical and then tweak seating depth to get rid of horizontal. It's not an exact science but it will get you close with minor tweaks. The fly in the ointment is situations like I started with a barrel that turned out to be a junker, between the tuner and jacking around with the load I wasted two months of the season before I threw the thing in the junk pile. To go down the road with the tuner without knowing if the barrel is any good is hard for your first experience, it wasn't Mike's tuner which I suspected at the time, it was the barrel. Kind of hard on the head.
 
There are a host of known loads that work well in the commonly used cartridges in SR BR. For example if a 6ppc won't shoot with 27.2 of LT31 and a light jamb on the bullet, then it likely won't shoot. There are also know loads with old school T32, N133 etc. As a general rule adjust the tuner to get rid of vertical and then tweak seating depth to get rid of horizontal. It's not an exact science but it will get you close with minor tweaks. The fly in the ointment is situations like I started with a barrel that turned out to be a junker, between the tuner and jacking around with the load I wasted two months of the season before I threw the thing in the junk pile. To go down the road with the tuner without knowing if the barrel is any good is hard for your first experience, it wasn't Mike's tuner which I suspected at the time, it was the barrel. Kind of hard on the head.


I want to clarify this, please. Tuners do affect horizontal too. IME, when the groups go straight vertical with my tuner, I'm 1 mark out of tune. Refer back to the photo I posted earlier. It's very typical of what I see with each tuner adjustment of only 1 mark at a time. Typically, The groups will stairstep right before going straight vertical, by a bullet hole or less. One more mark sucks them together.

I use to be more reluctanct to post things like that as such a matter of fact. But after several years and many barrels tested, it has become statistically significant, to the point of being boringly predictable. This is with MY tuner.
 
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So where are you centerfire guys starting with the tuner setting if you develop your load with the tuner on? Are you starting at setting 0, develop the load and then twist untill it shoots? Then chase the tune throughout the day? I ask because I know what I am looking for with rimfire and have an arbitrary number to get close with different length and profiles of barrels, but I am missing a big factor that you guys luckily can change and that is the load. Just curious to know how you all approach it. I would have to say that if I was going to do it tomorrow I would probably approach it the way Al outlines but at the limitations that Mike states, it may not be benifit of a new shooter to approach it that way.

Tad


Tad, with all due respect, rimfire shooters are the worst about over complicating tuners. Probably because of poor ammo quality/choices, magnified variables in said ammo and condition related changes such as wind drift, and a plethora of what I believe to be, bad info out there.

I chuckle when I hear people say that tuners work differently on rimfire. Two things change...in bore time and amplitude of vibration. Otherwise, the gun has no idea whether the cartridge has it's primer around the rim or in its center. In a nutshell, everything is slower and the tuner needs larger adjutments on a rimfire. By larger, I mean move the tuner no more than TWO marks at a time on a rimfire, vs 1 on a cf. Also, the range of tuner adjustment, between in tune and out of tune is about double. So, in a typical short range cf br rifle, there are almost always 4-5 marks between in tune and out, with my tuner. In rf, that's about 8-10 marks. Still, a very small and manageable window to work within without getting lost and confused with random tuner changes all over the place.

Without going into great detail as to why, I recommend starting with my tuner 1/2-1 full turn out from bottom.
 
So Calfee is wrong about setting his tuners once and then not moving them? I understand that he has done pretty well selling rimfire rifles with tuners. Do you know anyone that claims that he can do that with a CF tuner? Yes they both change tune when you move the weight. Beyond that, if you believe Calfee and the results that he claims, then there are significant differences. I do not believe that anyone claims that he can not change his load and not change his tuner and keep a CF rifle in tune.
 
So Calfee is wrong about setting his tuners once and then not moving them? I understand that he has done pretty well selling rimfire rifles with tuners. Do you know anyone that claims that he can do that with a CF tuner? Yes they both change tune when you move the weight. Beyond that, if you believe Calfee and the results that he claims, then there are significant differences. I do not believe that anyone claims that he can not change his load and not change his tuner and keep a CF rifle in tune.

He can do whatever he wishes, Boyd. Setting a tuner and never touching it, yet changing the load/ammo to affect tune, seems contradictory to me. Shooting a gun with a tuner that isnt in tune because you refuse to move it a mark or two, is not what id call the best way of utilizing a tuner. There are people in cf who have one on the barrel yet still load for tune changes, but they too are very few left.

So to answer your questions, imo, yes and yes.
 
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