Litz and Cortina - follow up on barrel tuner discussion

[gunsandgunsmithing]

Yes, thanks Mike for tagging me. I might have missed this thread if you hadn’t and look forward to reading through it when I get a minute…or many minutes apparently . Somebody did text me the video of the Litz-EC discussion and honestly I could only make it through an hour…my brain was hurt by the persistent pattern of Litz gently explaining the merits of scientific inquiry and stats while EC told numerous anecdotes. I’m not talking crap about those two but I was expecting something more substantial…maybe I didn’t stick around for that…I don’t know. Both approaches have their pros and cons. The big reason why I do a lot of testing is because I’ve heard so many conflicting anecdotes about the same phenomenon so I decided to let the test data inform me. This is why I am taking the time to do thorough testing on tuners. Certainly, anecdote has helped inform me about them as well as experts who have used tuners so I’m not discounting the value of anecdotes…they’ve actually helped me. But, I can conduct 10 hours worth of testing to answer what 30 years of certain anecdotes have derived which to me is the great value of testing. Also, I can do 10 hours of testing on something that would’ve required 30 years of anecdote which is something that rapidly advances our knowledge. This is the reason why I love the sign that hangs in Murdica’s tunnel that says “One test is worth 1000 expert opinions.” Anyway, thus far with the tuner testing, all of my data has been statistically significant and shows that the tuner can regain tune when using the same load in different barometric pressure conditions. The data is compelling to say the least. Now I’ll be testing temperature and humidity fluctuations…I see some 80-90 degree F days where I live coming up in the next few days so I’ll start collecting the data soon! Stay tuned! Haha…get it, stay tuned

Thanks again! I think you'll find that both matter. Keep up the good work, either way.

 

[blundby]

Yes, thanks Mike for tagging me. I might have missed this thread if you hadn’t and look forward to reading through it when I get a minute…or many minutes apparently . Somebody did text me the video of the Litz-EC discussion and honestly I could only make it through an hour…my brain was hurt by the persistent pattern of Litz gently explaining the merits of scientific inquiry and stats while EC told numerous anecdotes. I’m not talking crap about those two but I was expecting something more substantial…maybe I didn’t stick around for that…I don’t know. Both approaches have their pros and cons. The big reason why I do a lot of testing is because I’ve heard so many conflicting anecdotes about the same phenomenon so I decided to let the test data inform me. This is why I am taking the time to do thorough testing on tuners. Certainly, anecdote has helped inform me about them as well as experts who have used tuners so I’m not discounting the value of anecdotes…they’ve actually helped me. But, I can conduct 10 hours worth of testing to answer what 30 years of certain anecdotes have derived which to me is the great value of testing. Also, I can do 10 hours of testing on something that would’ve required 30 years of anecdote which is something that rapidly advances our knowledge. This is the reason why I love the sign that hangs in Murdica’s tunnel that says “One test is worth 1000 expert opinions.” Anyway, thus far with the tuner testing, all of my data has been statistically significant and shows that the tuner can regain tune when using the same load in different barometric pressure conditions. The data is compelling to say the least. Now I’ll be testing temperature and humidity fluctuations…I see some 80-90 degree F days where I live coming up in the next few days so I’ll start collecting the data soon! Stay tuned! Haha…get it, stay tuned

"Both approaches have their pros and cons"....I wonder what you think is advantageous of relying on anecdotes?

 

[Bryan Z.]

"Both approaches have their pros and cons"....I wonder what you think is advantageous of relying on anecdotes?

Without getting too deep into epistemology, first I wouldn’t “rely” on anecdotes unless that is the only information I have available and I have no means to verify the information. Even under that circumstance I wouldn’t rely on it but I would add it to my knowledge base as something with potential. Second, I place anecdotes within the “they may be on to something” category. If there is a reasonable degree of communality in anecdotes, then I would give some consideration that there may be something there that warrants formal testing.

 

[jackieschmidt]

Without getting too deep into epistemology, first I wouldn’t “rely” on anecdotes unless that is the only information I have available and I have no means to verify the information. Even under that circumstance I wouldn’t rely on it but I would add it to my knowledge base as something with potential. Second, I place anecdotes within the “they may be on to something” category. If there is a reasonable degree of communality in anecdotes, then I would give some consideration that there may be something there that warrants formal testing.

Bryan, a lot of shooters are like me. I have a lot of mechanical and structural talent. I can look at things and visualize exactly what it will take to work in a given application. I do this on a regular basis in my business.

But, when it comes to the engineering skills, particularly the mathematical part of it, I am very lacking. I have a rudimentary knowledge of differential calculus, but not enough to formulate proofs of any of the ideas that swirl around in my head.

One of the ideas that I came up with a number of years ago was the so called tuner with a dapenning feature. The first ones were an aluminum body with a rubber marine bearing pressed on to it, Gene Bukys and I did quite a bit of testing with the design, and he believed that the dampening feature widened the load window. I tended to agree, but have not proof other than anecdotal.

I wish I had the math skills to determine what happens to the vibration pattern of a typical barrel when it encounters the dampener on the end of the barrel.

Here is my latest design, it is basically a pieco of hard rubber machined out of a piece of a bumper on a pushboat. It is pressed on tight to the aluminum tuner housing.

 

[CharlieNC]

Bryan, a lot of shooters are like me. I have a lot of mechanical and structural talent. I can look at things and visualize exactly what it will take to work in a given application. I do this on a regular basis in my business.

But, when it comes to the engineering skills, particularly the mathematical part of it, I am very lacking. I have a rudimentary knowledge of differential calculus, but not enough to formulate proofs of any of the ideas that swirl around in my head.

One of the ideas that I came up with a number of years ago was the so called tuner with a dapenning feature. The first ones were an aluminum body with a rubber marine bearing pressed on to it, Gene Bukys and I did quite a bit of testing with the design, and he believed that the dampening feature widened the load window. I tended to agree, but have not proof other than anecdotal.

I wish I had the math skills to determine what happens to the vibration pattern of a typical barrel when it encounters the dampener on the end of the barrel.

Here is my latest design, it is basically a pieco of hard rubber machined out of a piece of a bumper on a pushboat. It is pressed on tight to the aluminum tuner housing.
View attachment 1438931

You can't calculate what happens during the first two milliseconds following the "explosion" when the bullet exits. The pretty vibrational frequencies which are calculated are just getting started after that point. But you can observe both of these phases using an accelerometer to see what's happening.

 

[Bryan Z.]

If I was in this “conversation”, and mentioned using my tuner to induce about a bullet hole worth of vertical in my 30BR VFS Rifle to get out of a horizontal tune, I bet both of these guys would look at me like I was nuts.

Well, with my data, you wouldn’t look nuts to Litz. I shot several 5-shot groups, measured them, assessed group shape, and ran the stats. This is now a statistically significant finding so mention away!! I’ll be honest, I was expecting a little more random variation in group size and shape but the vertical showed up over 50% of the time and then after turning the tuner 1 hash, it disappeared completely with 100% circular groups. I was quite amazed at how obvious the regain tune function of the tuner performed.

 

[gunsandgunsmithing]

Well, with my data, you wouldn’t look nuts to Litz. I shot several 5-shot groups, measured them, assessed group shape, and ran the stats. This is now a statistically significant finding so mention away!! I’ll be honest, I was expecting a little more random variation in group size and shape but the vertical showed up over 50% of the time and then after turning the tuner 1 hash, it disappeared completely with 100% circular groups. I was quite amazed at how obvious the regain tune function of the tuner performed.

I'm still amazed at how predictable the shapes are. Amazed is just a good word for it but when you do vibration analysis and see bullet exits occur on either side of a sweet spot at top or bottom of the swing, those shapes actually start to make sense and moving a tuner is no longer random at all.

Read that again, please. And Bryan, think about how those shapes may well(do) correspond to muzzle position along a pretty sharp sine waveform.

 

[Bryan Z.]

I forgot to reference the data that I collected. It’s summarized in the series of videos. Here are the latest videos:

DSB Fabrication tuner:

Harris tuner:

Mike, you mention amazing…I will admit I was amazed at the striking similarities in the data with the two vastly different tuner types. In scientific terms, we can now say that the regain tune finding has been replicated.

The more replicated findings in well-controlled studies, the stronger the evidence. Guidelines to call something “evidence-based” vs. “promising” would now categorize the regain tune function as “evidence-based.” The regain function is what Jackie was describing where a small turn of the tuner can reduce or eliminate vertical dispersion (loss of tune) and turn the shape into a nice circle (regain tune). Of course, the group size itself is reduced when regaining tune.

 

[dcali]

Bryan, a lot of shooters are like me. I have a lot of mechanical and structural talent. I can look at things and visualize exactly what it will take to work in a given application. I do this on a regular basis in my business.

But, when it comes to the engineering skills, particularly the mathematical part of it, I am very lacking. I have a rudimentary knowledge of differential calculus, but not enough to formulate proofs of any of the ideas that swirl around in my head.

One of the ideas that I came up with a number of years ago was the so called tuner with a dapenning feature. The first ones were an aluminum body with a rubber marine bearing pressed on to it, Gene Bukys and I did quite a bit of testing with the design, and he believed that the dampening feature widened the load window. I tended to agree, but have not proof other than anecdotal.

I wish I had the math skills to determine what happens to the vibration pattern of a typical barrel when it encounters the dampener on the end of the barrel.

Here is my latest design, it is basically a pieco of hard rubber machined out of a piece of a bumper on a pushboat. It is pressed on tight to the aluminum tuner housing.
View attachment 1438931

As someone who has spent a fair amount of time calculating vibrational behavior, the first question I'd ask about this setup is "can you reproduce the results with an equal weight of aluminum in place of the rubber?"

Why? Because from a physical/theoretical point of view, you can think of any vibrating system as a spring, a weight, and a damper. the spring and the weight determine the frequency of the vibrations, and the damper sucks energy out of the system, changing the overall dynamic response.

Intuitively, my gut says a small amount of rubber attached like that would not be capable of absorbing much energy, and therefore wouldn't impact the dynamics much as a damper. But it has significant weight, and weight clearly matters. So what you were seeing may simply have been the effect of the additional weight.

I have to emphasize that that is conjecture based on experience analyzing all manner of aerospace structures. I reserve the right to be wrong. But that's the first thing I'd look at.

Which brings me back to a question I've asked myself about Harold Vaughn's experiment with lead sleeved barrels. I don't think He explained his reasoning other than that he was trying to slow the barrel down. (it's been a while since I read it). But you can do that much more easily with a weight on the end. So why the complexity of trying to get a lead sleeve to stick to the barrel? I wonder if the goal wasn't to use the very low yield strength of the lead as a damping mechanism. A lead sleeve very well could materially impact damping, and i think exploring dampers is an interesting and valid thing to do. I'm just not sure how you'd best do it. Maybe an oil or sand filled sleeve. Whatever the mechanism, it has to be capable of transforming a significant portion of the barrel's kinetic energy into heat. I'll add that I don't know what "significant" actually means in this context.

If one really wanted to go nuts, we used magnetic dampers on space shuttle cargo. Really strong magnets are dirt cheap these days...

 

[jackieschmidt]

I did a grand experiment back in 2000 with my Unlimited Rail Gun.

I decided to enclose the barrel in a 2 1/4 inch ID x 3/16 wall tube, with the 1.450 diameter barrel having a layer of pourable Devcon between it and the Tube’s ID.

It was a lot of work, making all of the alignment rings to center the barrel.

How well did it shoot. Good enough to win two Region Championships and the NBRSA Unlimited 100 at the 2000 Nationals.

I quit doing it because it was simply too much work.

It did completely deaden the barrel, not to mention adding quite a bit of mass.

The thing was, it would go out of tune just like any other Benchrest Rifle. But when it was right, it was right all the way.

Here is a picture of it at the 2000 Nationals. The picture got water damaged during a hurricane. The young guy is me, before time caught up. You can make out the barrel assembly Well enough to get an idea.

 

[dcali]

I did a grand experiment back in 2000 with my Unlimited Rail Gun.

I decided to enclose the barrel in a 2 1/4 inch ID x 3/16 wall tube, with the 1.450 diameter barrel having a layer of pourable Devcon between it and the Tube’s ID.

It was a lot of work, making all of the alignment rings to center the barrel.

How well did it shoot. Good enough to win two Region Championships and the NBRSA Unlimited 100 at the 2000 Nationals.

I quit doing it because it was simply too much work.

It did completely deaden the barrel, not to mention adding quite a bit of mass.

The thing was, it would go out of tune just like any other Benchrest Rifle. But when it was right, it was right all the way.

Here is a picture of it at the 2000 Nationals. The picture got water damaged during a hurricane. The young guy is me, before time caught up. You can make out the barrel assembly Well enough to get an idea.View attachment 1439164

This is fantastic. I think you were on to something.

 

[gunsandgunsmithing]

very different that Jackie's tube setup but a few years ago I bought some .080(iirc) thick heat shrink tubing and shrunk it around a great bbl. I could never make it shoot like that. Still no real idea why but it didn't matter what I did, it wouldn't shoot like it did before. Not terrible but nowhere near what it was like without it.

Any thoughts...anyone?

 

[jackieschmidt]

As a note, Charles Huckabe, one of the best Group Shooters of all time, wrapped the taped lead weights used on golf clubs around his Unlimited Barrels.

I don’t know if it really helped, but it sure didn’t seem to hurt.

 

[gunsandgunsmithing]

very different that Jackie's tube setup but a few years ago I bought some .080(iirc) thick heat shrink tubing and shrunk it around a great bbl. I could never make it shoot like that. Still no real idea why but it didn't matter what I did, it wouldn't shoot like it did before. Not terrible but nowhere near what it was like without it.

Any thoughts...anyone?

All I can say is, it's not ALL about damping but damping DOES play a role. I've tested just about everything, including many viscosities/durometers of rubber and even vibration dampening specifics like non-newtonian polymers and silicones. The best I've found is what I use...tungsten powder, even down to specific mesh size. Not knocking anybody or anyone'ss design but o-rings and rubbers on the outside have more benefit as a grippy surface than as a damper in this application, according to my testing and results. I should add...YMMV.

 

[ImBIllT]

No time like the present to jump back in. Everything from then still works. You probably had a barrel from Wisconsin, hodgedon extreme powder, Berger bullets and Lapua brass.

Don’t have the time right now, but it’s on the horizon somewhere. Might be two years, might be five. I have an F-open rifle that I built about 8 years ago and have only used to fire-form 50 pieces of brass for a hunting rifle of the same cartridge.

 

[Davidheart]

Bryan, watched your videos. Did not read the whole thread. Your comments in regard to barometric pressure variations and group changes would explain why even standard hunting guns just "don't want to shoot today.'

Your findings teach me, for those not equipped with a tuner, when we do our load development there are far more factors at play than wind and temp sensitivity. We should note not only the temperature a load was developed but barometric pressure and humidity. It would be unreasonable to expect identical group results from a good shooting hunting rifle unless all factors were identical from day to day.

I've fitted a number of DSB tuners for customers but hadn't the chance to see their results in person. Good to see. Thank you for your time and keep up the good work.

 

[Bryan Z.]

Just want to throw something out there regarding speculation about the causal mechanism(s) of tuners: you don’t know what you don’t know or you do know what you don’t know. Hopefully one day we can go beyond low n studies, anecdotes, and “studies” with limited technologies that yielded circumstantial (at best) evidence into a world of studies that yield tight linkage between theory and outcome data.

 

[Konocti's Wigwam]

Bryan, watched your videos. Did not read the whole thread. Your comments in regard to barometric pressure variations and group changes would explain why even standard hunting guns just "don't want to shoot today.'

I'd like to know also. Mainly because I don't see the accuracy as being critical for hunting. Even if you think about using a red dot using a 4 MOA scope. So how much are we talking about, say 50 yards it's only 2", and even if you think about 4 MOA at 100 yards, 4" is a pretty big target for most anyone.

I haven't watched their video, but atmospheric condition has effect on the actual velocity. I can see how a tuner on the end of the barrel might be able to adjust that, so that in the case where accuracy is critical, it can be dialed in.

In F-Class or PRS or whatever people shoot in, everyone shows up and plays in the same conditions, so people thinking outside of the box tend to have an edge on their competition.

But if you're shooting a feral pig at 100 yards, you're still gonna end up with a dead pig. You can even hit them in the gut, be 12" off from the vital zone and the pig will still bleed to death, where in competition even .1-.2 MOA may win a tournament. I am not any type of precision competitor. Guys like Eric, Bryan, Speedy, F-Class John, you guys are way above my pay grade...I'm just looking for a pig, at the cost of $28.08/ea.

 

[Davidheart]

..... Mainly because I don't see the accuracy as being critical for hunting.....

But if you're shooting a feral pig at 100 yards, you're still gonna end up with a dead pig. You can even hit them in the gut, be 12" off from the vital zone and the pig will still bleed to death..... just looking for a pig, at the cost of $28.08/ea.

I understand your sentiment regarding a lower accuracy priority when it comes to hunting rifles. I don't entirely disagree with it but....

We may not need .1" groups to kill an animal at 100 yards, however there is a much wider variance in field conditions when hunting than in competition. If your gun shoots 2" at 100 in the best conditions at the range that 2" @ 100 turns into 12" or more very quickly in the worst circumstances. What's more, a gut shot animal could run forever before finally dying somewhere in the next county.

I believe a hunting rifle should not be fielded if it isn't shooting 1" or less @ 100.

Didn't Browning have a "tuner" of sorts on their rifles for a time?

Edit: Found the Browning tuner. The BOSS tuner. https://www.browning.com/news/tech-terms/boss-rifle-accuracy-system.html

Snip from the website: "

How does the BOSS work?​

The BOSS simply tunes the vibrations of your barrel. This allows the bullet to leave the barrel the split second it is stationary. Your BOSS manual has a list of settings for each caliber and bullet weight. Adjusting your BOSS to these "Sweet Spot" settings allows you to find the instant your barrel is stationary. The result is accuracy never achieved before by an out-of-the-box rifle."

 

[jonbearman]

Does he neck size now ?

He always full length sizes now.