Advice for Bryan Litz on barrel tuners.

[darkangel_r2]

15.1 Simple Harmonic Motion | University Physics Volume 1

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Spring Mass System - Definition, Spring Mass System in Parallel and Series Combination

Spring Mass System - Get a complete overview of the spring mass system along with key topics, diagrams, equations and look at various problems with solutions.

byjus.com

Horizontal spring with a mass is a simple model of a barrel with a tuner undergoing elastic deformation (ie bending/ vibrating in a way that doesn't permanently deform the barrel in the horizontal plane). Cantilever bending is better approximation but the math is worse so this will likely just get us a comparative relationship (as this goes up or down this other thing goes up or down).

w= frequency
k= barrel stiffness
m=tuner mass
x=displacement from neutral
PE =potential energy which is equal to the energy that is put into the barrel by the gun shot. Its max value can be considered a constant when using the same load.
KE= kinetic energy put into the barrel by the gun shot. Its max value is equal to PE and can also be considered a constant with the same load.

In the horizontal plane the tuner does not significantly reduce barrel rigidity due to its added weight. Not sure if vertical does.

w=(k/m)^.5
PE=1/2kx^2
KE=1/2mv^2

Horizontal plane:
As the mass of the tuner increases the frequency of vibration goes down and velocity of the vibrations go down. A significant positive. A larger node.

As the barrel gets stiffer the frequency increases. Not good. A smaller node. Lucky for us making a barrel more stiff usually happens in the form of adding mass to the barrel so it partially cancels the increase in frequency by now having more mass to move.

As the barrel gets stiffer the amplitude of the vibration goes down. A good thing less dispersion.

Adding a tuner will slightly reduce the amplitude in the horizontal due to real world conditions providing some dampening.

Vertical: Will have the same effect on frequency. May possibly make amplitude worse (possibly a good thing if you want positive compensation out of a very stiff barrel).

So slightly less amplitude in horizontal (maybe slightly more in vertical) and much lower frequency and muzzle velocity in both combined with repeatable control over the muzzle position on exit. If you can afford the extra weight a quality barrel tuner is a very nice tool. Lowering the frequency and velocity of vibration has a significant positive effect on dispersion of any round fired. Also in any application where the rifle touches the shoulder the hinge point for the whole system is pretty far back so adding a mass at the muzzle has a big effect on how much the muzzle moves because of recoil while the bullet is still in the barrel.

I think the tuner brake is a thing we are going to see on a lot of rifles in the future. A conservative brake already weighs nearly enough to tame narrower profile barrels. So adding a small tuning mass to the brake adds a lot of functionality to that system as long as the brake itself is easy to clean as carbon fowling has mass.

I have not read the new Litz book yet so I can't intelligently comment on his methodology.

 

[BoydAllen]

JFC, you're like a broken record.

Yes, I (and pretty much everyone participating in the discussion) understand basic tuner theory of operation.

Read what I said. If you don't like his test *results* and don't think they reflect how your gun behaves... replicate the test, exactly, including the # of groups fired and the data acquisition, crunch the numbers and *prove* him wrong. Don't sit there behind your keyboard whining about it with anecdotal examples.

Are you serious? If someone does a study with what appears (to me) to be flawed methodology, my go to option is just to ignore it and go on with my life, with the possible exception of discussing it. No I have not bought the book, and my opinion is based solely on information furnished in this thread. If that information is incorrect, well then I guess that I will have to live with my flawed opinion, but since I have some experience with tuners and have discussed their use with many who have chosen to use them, whose records would tend to validate their expertise, why exactly would I need to read a study done by someone with no apparent experience in the area of shooting that I choose to be most interested in?

 

[D Coots]

Tony Boyer, the best short range Benchrest shooter of all time attained 176 points in the Hall of Fame, second place is Wayne Campbell at 63 or so.

Tony never used a tuner that I ever witnessed.

After watching him shoot a group at 200 yards one time at the Supershoot in a complete reversal without going to the sighter, 3 shots in red, 2 in green, probably a 3 something group, I asked him after the match how he did it. He pointed to his head and said, IT'S ALL IN THE COMPUTER.

He wasn't much on computers or theories, but he was big on DOING.

Later
Dave

 

[GetReal]

I think my tuner showed good results on my Vudoo 22rf F-class gun.

I would never presume to tell Bryan Litz anything at all about bullets or accuracy.

 

[Bill Norris]

Tony Boyer, the best short range Benchrest shooter of all time attained 176 points in the Hall of Fame, second place is Wayne Campbell at 63 or so.

Tony never used a tuner that I ever witnessed.

After watching him shoot a group at 200 yards one time at the Supershoot in a complete reversal without going to the sighter, 3 shots in red, 2 in green, probably a 3 something group, I asked him after the match how he did it. He pointed to his head and said, IT'S ALL IN THE COMPUTER.

He wasn't much on computers or theories, but he was big on DOING.

Later
Dave

But on the other hand how does that possibly mean tuners DON"T work?

 

[gunsandgunsmithing]

But on the other hand how does that possibly mean tuners DON"T work?

With very few exceptions, the only people that still believe that tuners don't work fall into two distinct categories. One category is they have no experience with tuners at all. The other category is made up of people who randomly move tuners, without rhyme nor reason, yet expect predictable and repeatable results from them. Simply put, use it right or don't use one. But most anyone that has put in the time to learn how to tune with powder charge and or seating depth can quickly learn how to properly use a tuner to their own benefit. You just have to keep an open mind and be very methodical. i.e...I don't know anyone that chases tune in small br type cartridges in 1 full grain increments. So, why would they move a tuner in full revolutions, for example. There is a methodology to it. Without that, you will almost certainly chase your tail and be lost with one. My tuning method is based on breaking it down from completely in tune, to completely out of tune AND quantifying group SHAPES at each setting in between. I've done the leg work for ya already and can tell you that with MY tuner on a typical cf br rifle, it's only 4-5 marks between totally in tune to totally out. Each mark is .001". So, a very tiny amount of tuner movement is all it takes and it's up to the shooter to establish mark values relative to group shapes for those 4 or 5 groups from in to totally out of tune. We're talking 4 or 5 group shapes to recognize and when groups form diagonally up and to the right, we can rule wind out, from a rh twist bbl. They really are a lot easier to use than to debate on a forum. I do this because there is still so much purely bad info out there regarding tuners in general. So many world records and national championships support their use and that they are no longer some kooky theory, is foregone to most and the rest probably did or still do struggle with tuning by ANY method. Often, it's easier to teach someone how to use a tuner if they have never shot a br rifle and their head hasn't been filled with false information from people who may have the best of intentions but lack any understanding of how tuners work and do what they do. To those that have used tuners but move them in relatively large increments, I ask a few questions...Why do you move it in that particular amount at a time? IOW, what is it based on. Why not bigger or why not smaller increments? Do you know what the groups should shape up live when completely out of tune, completely in tune..and for each adjustment in between? Frankly, anyone that can't offer very specific answers to all of those questions is very likely guessing.

 

[Ccrider]

But on the other hand how does that possibly mean tuners DON"T work?

Dang, I was thinking the same thing.

 

[D Coots]

But on the other hand how does that possibly mean tuners DON"T work?

Nope...to each their own...go for it. Use what you want. How many points do you have ?

I didn't say tuners don't work. Just beat his record any way you want.

Ain't gonna happen by typing.

Later
Dave

 

[gunsandgunsmithing]

Dang, I was thinking the same thing.

He and Gene Bukys are/were two of the best ever to walk the earth at keeping a ppc in tune with n133. I never agreed with Gene in how he used a tuner but I concede that they do widen the tune window some, which is how and why he used a tuner. He still adjusted the load rather than move the tuner. It's not how I use one and I've always felt he was leaving the best part of a tuner on the bench by his method. But, if I was one of the top 2 or 3 in the world at tuning with powder charge, and the weight on the end of the bbl only made that fact even more so...I can't blame him for using what God and hard work gave him.

 

[Bill Norris]

Nope...to each their own...go for it. Use what you want. How many points do you have ?

I didn't say tuners don't work. Just beat his record any way you want.

Ain't gonna happen by typing.

Later
Dave

I don't compete except with myself and I would never argue with a man with a record period. But, nothing about his record says tuners don't work. It simply says Tony did not chose to use one.

 

[Dusty Stevens]

You can tune with seating depth, powder and neck tension the exact same way you can with a tuner. A tuner gives you the advantage of doing that tuning after the rounds are loaded

 

[D Coots]

He and Gene Bukys are/were two of the best ever to walk the earth at keeping a ppc in tune with n133. I never agreed with Gene in how he used a tuner but I concede that they do widen the tune window some, which is how and why he used a tuner. He still adjusted the load rather than move the tuner. It's not how I use one and I've always felt he was leaving the best part of a tuner on the bench by his method. But, if I was one of the top 2 or 3 in the world at tuning with powder charge, and the weight on the end of the bbl only made that fact even more so...I can't blame him for using what God and hard work gave him.

Gene didn't use a tuner, he was using a subber as he called it and marketed it back then. Nothing against Gene, but he wasn't in the same universe with Tony in the game. Lot's of guys are still using Gene's snubbers to widen the load window. It must work.

Later
Dave

 

[D Coots]

You can tune with seating depth, powder and neck tension the exact same way you can with a tuner. A tuner gives you the advantage of doing that tuning after the rounds are loaded

Too late. If your seating depth is off, neck tension is off, and your powder charge is off, you'll be playing Ketchup every group as the day wears on IMO.

Later
Dave

 

[gunsandgunsmithing]

15.1 Simple Harmonic Motion | University Physics Volume 1

courses.lumenlearning.com

Spring Mass System - Definition, Spring Mass System in Parallel and Series Combination

Spring Mass System - Get a complete overview of the spring mass system along with key topics, diagrams, equations and look at various problems with solutions.

byjus.com

Horizontal spring with a mass is a simple model of a barrel with a tuner undergoing elastic deformation (ie bending/ vibrating in a way that doesn't permanently deform the barrel in the horizontal plane). Cantilever bending is better approximation but the math is worse so this will likely just get us a comparative relationship (as this goes up or down this other thing goes up or down).

w= frequency
k= barrel stiffness
m=tuner mass
x=displacement from neutral
PE =potential energy which is equal to the energy that is put into the barrel by the gun shot. Its max value can be considered a constant when using the same load.
KE= kinetic energy put into the barrel by the gun shot. Its max value is equal to PE and can also be considered a constant with the same load.

In the horizontal plane the tuner does not significantly reduce barrel rigidity due to its added weight. Not sure if vertical does.

w=(k/m)^.5
PE=1/2kx^2
KE=1/2mv^2

Horizontal plane:
As the mass of the tuner increases the frequency of vibration goes down and velocity of the vibrations go down. A significant positive. A larger node.

As the barrel gets stiffer the frequency increases. Not good. A smaller node. Lucky for us making a barrel more stiff usually happens in the form of adding mass to the barrel so it partially cancels the increase in frequency by now having more mass to move.

As the barrel gets stiffer the amplitude of the vibration goes down. A good thing less dispersion.

Adding a tuner will slightly reduce the amplitude in the horizontal due to real world conditions providing some dampening.

Vertical: Will have the same effect on frequency. May possibly make amplitude worse (possibly a good thing if you want positive compensation out of a very stiff barrel).

So slightly less amplitude in horizontal (maybe slightly more in vertical) and much lower frequency and muzzle velocity in both combined with repeatable control over the muzzle position on exit. If you can afford the extra weight a quality barrel tuner is a very nice tool. Lowering the frequency and velocity of vibration has a significant positive effect on dispersion of any round fired. Also in any application where the rifle touches the shoulder the hinge point for the whole system is pretty far back so adding a mass at the muzzle has a big effect on how much the muzzle moves because of recoil while the bullet is still in the barrel.

I think the tuner brake is a thing we are going to see on a lot of rifles in the future. A conservative brake already weighs nearly enough to tame narrower profile barrels. So adding a small tuning mass to the brake adds a lot of functionality to that system as long as the brake itself is easy to clean as carbon fowling has mass.

I have not read the new Litz book yet so I can't intelligently comment on his methodology.

A couple of points. First I agree with I think all of that but, one thing that always stands out to me when I read or discuss tuners from a physics/scientific standpoint is related to amplitude. Physics does in fact teach us that adding a mass to the end of a cantilevered beam should REDUCE amplitude. I won't disagree with that except to bring up an important and usually overlooked aspect of that. We are dealing with a very very short period of time, the time the bullet is actually in the bbl. From vibration analysis testing..the testing shows that amplitude is actually INCREASED during that roughly 1.5 milliseconds while the bullet traverses the bore. And, it makes perfect sense when you consider that the bbl is already deflecting downward before you even pull the trigger due to the weight at the end and gravity. Bottom line...it does in fact increase amplitude for that very short period of time.
Next, I consider increased amplitude a good thing..not a bad one because it's muzzle deflection that we see on target, which "talks to us", showing tune or lack of, more clearly on the target. I have tested this a fair amount and have been working with a bbl maker that has made me about 20 barrels in a contour that I spec'd for this purpose..making it slightly less stiff, intentionally. I've found that I prefer this over stiffer barrels to a point and for this reason. It's not drastically different than we already use. It's quite similar to a typical LV contour bbl, fwiw. That also brings up a point about bigger bbls. Fatter doesn't necessarily mean stiffer overall. It is on a per in basis but not necessarily at typical lengths used.

Last thing that comes to mind is horizontal...Tuners do affect horizontal as well as vertical. A big part of why is twist of the rifling but nonetheless, they do vibrate in all planes, apparently, but are biased toward the vertical plane due to gravity....

I think that's all I was gonna hit on. Ultimately, shooters want to know how to make tuners work for them more than how they actually do it but it is very worthwhile to me and some to have a better grasp on what's going on.

In it simplest terms, tuning is timing bullet exit to ideal muzzle position. This is true be it with a tuner or by changing powder charge.

 

[gunsandgunsmithing]

Too late. If your seating depth is off, neck tension is off, and your powder charge is off, you'll be playing Ketchup every group as the day wears on IMO.

Later
Dave

Respectfully, I disagree and must ask, do you use a tuner, which one and how do you go about it?
I didn't disagree with a "snubber" or whatever you choose to call it, widening tuning windows. Just the opposite..I agree with that, albeit a small amount and that is quantifiable by measuring frequency. Yes, I've measured it. It does have some value, alone. If just a snubber, why did he add numbers to it? Why not just randomly screw it on somewhere and do your load work up? We could debate the effectiveness of the design but I don't see the point in that, but his tuner was a motivating factor in how and why I make mine the way I do, as a very efficient dampener as well as a tuning device. True enough though, his earlier tuners did not incorporate numbers on them, fwiw.

 

[D Coots]

No tuner, yet. What you speak of may be true. Fine. So far I've never been beaten in a match by gunsandgunsmithing with a tuner. No problem with them, have some, bring it on.

Later
Dave Coots
Not an alais....

 

[gunsandgunsmithing]

What you speak of may be true. Fine. So far I've never been beaten in a match by gunsandgunsmithing with a tuner. No problem with them, have some, bring it on.

Later
Dave Coots
Not an alais....

That's a 2-way street Dave. Why don't you travel over and shoot with us. You'll either win or there's a good chance whoever does win, has one of my tuners on their gun. Sorry, but you're response is you avoiding the questions I asked. So, I assume you are badmouthing something you don't have any experience with. Fair enough?

edit..
--Mike Ezell
..not an alias either, my friend. It's in my signature line and I've been an avid poster here since about 2007. No, not an alias at all. I could guess what the D stands for in you handle but I'll be respectful and say that, while I don't know you personally, I do know who you are. You probably knew my name too but that may be a wrong assumption on my part.

 

[D Coots]

Sorry, I don't shoot score. Can't be competitive with a small diameter PPC.

Later
Dave

 

[gunsandgunsmithing]

Sorry, I don't shoot score.

Later
Dave

Ahhh, so not only do you know who I am but the game I prefer to shoot. How bout dat? Can I guess why you don't shoot score or are you just gonna leave that out there like group is superior in some way?

In my case, I prefer score but if there were group matches close by, I'd shoot group too...but I can shoot score just about every weekend here within 45 minutes to about 2.5 hrs away. Or, I could drive 5 hrs each way and shoot a couple of group matches all year long.

 

[D Coots]

Nope, don't know who u r, but didn't take long to figure out which game you shoot...who cares, but you? You're the one insinuating which game is superior. I don't care. Shoot what you want, I'll do the same. Don't care, have fun. Come beat me if you have a likin to, you won't be gettin no cherry, and I ain't scared , bring it on...

Later
Dave