Two-flats

Leuchkafer (RabidM4U5?), if there were such a thing as .22LR match ammo with perfect consistency, it wouldn't be necessary to use a tuner to improve results. With the shooter and wind out of the equation, with all else equal only a better barrel could achieve that.

Meanwhile, in the absence of such miracle ammo, shooters attempt to, as you put it, "nail down positive compensation and how to achieve it with different barrel/ ammo variables". On what ammo variable do you think a tuner works most significantly?
 
I believe that's what I'm trying to illustrate by giving data such as the frequency in Hz required. In theory, I should be able to achieve this value in the workshop with a rubber mallet to ring it like a xylophone, providing I had an easy way to measure how it was moving. Perhaps a high speed camera would be required. I'm well aware that most people out on the internet just slap one on and spin it randomly. I also try to point out that this often doesn't work, and thought I had been doing so in this thread and a couple of the other tuner threads. Another intention of mine at the moment has been to show my work, as it were, whenever I finally make it out to the range with my new stash of ammo. Unfortunately for me, I'm stuck waiting for my club to get the range sorted out so 50-yard shooting is allowed again. Until that happens, I'm stuck twiddling my thumbs and cursing a crapload of money sitting on the shelf that I can't spend, heh. I've already done this work several times with a few guns/barrels, but thus far haven't kept really good records of the process and results. So that's what I'd like to actually do this time. In the past, once we got one of the guns into the correct region all that stuff was just thrown away because we didn't need it anymore.

The compensation being spoken of is for muzzle velocity differences. The whole point of getting the barrel in an upswing of a certain rate is so that its upswing rate itself is going to change the angle of departure for every round according to its muzzle velocity. A 1035 fps round needs a departure angle of 10.954 MOA in order to hit zero at 50 yards. A 1075 fps round needs a departure angle of 10.405 MOA in order to hit zero at 50 yards. That's a difference of 0.549 MOA with a difference in muzzle exit time of 0.106666667 milliseconds. That gives a required barrel upswing rate of 5.146875 MOA per millisecond. Which means if you get your barrel so that it is in an upswing of that rate during the period of time when bullets exit it will compensate the amount of departure angle for all shots within a reasonable variation in muzzle velocity.

Obviously if you had theoretically perfect ammo that was always precisely the same velocity you would want a barrel that did not move whatsoever to pair with it. The fact of the matter is, neither of those things exist. So, how else can you try to make shots go through the same hole when you're left with ammo that varies and barrels that move? Find the best ammo you can manage. Try to control the barrel's movement as much as you can manage. And that's what has brought us around to the idea of positive compensation. People before me have figured it out. And some have even tried explaining it and how to go about it, but it tends to fall on deaf ears. It seems to fall on deaf ears, one, because some people don't understand it and just dismiss it because of that. Two, even if they believe it they may not understand it well enough to go about finding it in a straight forward manner. As an idea it isn't super complex, but how to reach it isn't super easy. You've got to understand what's going on, and how to affect things in a controllable manner. Most people's understanding of the subject seems to start and stop at "Buy tuner. Install tuner. Randomly spin tuner." I think I've shown how this is an oversimplification that isn't always going to lead to positive results. When even a guy like Bryan Litz decides to run a test to see if tuners work and he comes away with the idea that they don't because he couldn't get any repeatable results it kind of says something about the amount that most people do not know about them and how they work. Essentially, he did the "buy tuner, install tuner, randomly spin it" method of testing them. Since he used (I believe) a CZ 457 for this test, he wasn't exactly using a good rifle, nor a typical benchrest barrel. You pretty much need a barrel that resembles very closely what was used in the design of the tuner you're using or you won't be able to get good results with it. A Harrell tuner weighs a certain amount. And the barrels they're usually installed on are all very typical, similar benchrest barrels. When everybody is using 0.920" 26" barrels (or whatever the most popular dimensions are, that's just a fuzzy guess at remembering) and are getting good results with Harrells on them, it stands to reason that this is exactly what the Harrell was meant to be used on. But taking some CZ factory barrel that's nothing like that and putting the Harrell on it isn't likely to produce any good results. Its vibrational behaviour is just going to be too different from the vastly different benchrest barrels that it was meant to be used on. Might you get lucky and find it helps at some mode? Perhaps. There are a lot of harmonic modes involved, and maybe you'll be able to get some positive results with one of them. But it isn't very likely to be the fundamental mode that you're playing with, because your barrel is just too different from the intended barrel.

Even in my method there is still some trial and error, because measuring the speed of the barrel directly is not an easy thing to do. But my method can drastically cut down on the amount of trial and error that you have to partake in. After my recent lot testing of Eley Tenex and the five different lots that my supplier had a decent amount of available for purchase I found that one lot performed quite a bit better than the other four in my barrel, and when I asked how much of that lot he had left it was unfortunately not a full case, which I wanted to buy. He only had 7 bricks of it left. This lot just happened to be the slowest of the five, listed at 1060 fps. So I took all of that lot that he had left, but I still wanted a full case of ammo. So I had him send me 3 bricks of another lot to pad it out, and I chose the lot that was listed at 1075 fps, but not because it was the lot that shot second best. I think maybe that one actually shot third best, but that wasn't why I wanted it. I wanted that lot as second choice because I wanted another lot that had a noticeable speed gap from the first choice lot. That one was the second fastest of all lots, but the fastest may have been the worst shooting, so I compromised. So I've got 7 bricks that'll be used mostly for matches, and 3 bricks that'll be used mostly for testing. But the testing is going to require using some of both.
 
If I shoot a target that gives me a 25-shot group, and you can obviously calculate where the centre of that group is. If I shoot targets with each lot, and don't touch the scope, that will give me virtual cetnres that I can compare, giving me an offset between the two lot numbers. From there, the theory of positive compensation takes over. One will be offset above/below the other in elevation. One can then imagine their barrel is going to have a curve similar to one of these:



Was the slower lot printing above or below the faster lot? How does that change when you add some mass to the muzzle? That should help you determine how much mass you need to add. But unless you've got some easy way to measure the speed of the barrel directly you're going to be left to some trial and error to narrow down just how much mass you need to add to make it swing at the desired rate. The more mass you add, the more you stretch that curve out to the right, making it take longer and longer for those motions to occur. As you approach the correct amount of mass you're going to see less and less vertical on target. If you see the amount of vertical decreasing and decreasing, but then increasing again, well, then you know you've gone too far. It would obviously get pretty expensive to shoot a full target for every interval of mass you care to try. You can try to cut that expense down by shooting 5-shot or 10-shot groups instead, obviously accepting more error by doing so, though. But say I shoot a target with the slow lot and the fast lot and I see that the slow lot is printing above the fast lot. Then I know I'm in business, because that's what you want to see. When you have a slower lot printing higher on target than a fast lot then you are already in the region of positive compensation. When you see a slower lot printing lower than a faster lot then you are in the region of negative compensation, the barrel is in a downswing during bullet exit. When you see a slower lot printing higher than a faster lot, as you add more mass you should see the lots begin printing closer together. Say you see them printing with a 0.25" offset. So you add some more mass and test again, and this time you see a 0.125" offset. OK, you're getting closer. Add more mass and test again, and this time the slower lot has switched places, and is not printing 0.063" lower. Now you've added too much, and it has slowed the barrel down past where you want it. So you test with mass in between the last two, because the second last one it was still printing above, but the last one it began printing below. This indicates the correct amount of mass is going to be somewhere between those last two. The closer and closer you get to the correct amount of mass, the closer and closer the offset between the two lots is going to get.

And you should be able to decrease the number of times you have to play with yet another different amount of mass by using a binary search. When you know your goal lies between two extremes you can cut the number of search attempts dramatically by testing at the halfway point between the extremes. So if you know that it begins behaving the way you want it to at 50 grams, and stops behaving the way you want it to at 150 grams, then you can focus between 50 and 150 grams. You know 50 is showing the correct trait, but the amount of that trait isn't enough. And you know 150 is showing the correct trait, but is close to being too much. So, a binary search. You split the difference and test 100 grams. It also shows the correct trait. What's closer to the ideal? 50 and 100? Or 100 and 150? Say 100 and 150 are closer than 50 and 100 are. Split the difference again, and test 125. What's closer to ideal now, 100 and 125, or 125 and 150? 100 and 125 are closer? Alright, split the difference again. Test 112. 112 and 125 are closer to ideal? Split the difference again and test 118. 112 and 118 closer? Test 115 next. At some point you're going to reach a point where it just gets to be too difficult to see if it even matters anymore. If you already know some useful extremes then a binary search usually gets you to your ideal in just 7 or 8 steps. So rather than having to test between 50 and 150 grams in, say, 1-gram intervals and the resulting 100 steps, you can do a binary search and reduce that to just 7 or 8 steps. At which point you should be printing nice, small, round groups. And if you want to wring as much as you possibly can out of it, you build a proper tuner that is in that mass ballpark, going slightly less since you can move a portion of its mass outwards to really dial it in finely.
 


As I mentioned before, I found that my Harrell was too heavy for this barrel. You can see it on the left, along with a lighter copy in the middle that I drew up and 3D-printed, and yet another test subject on the right. The one in the middle is something like 103 grams, or near that. I was testing with some Lapua Center-X at the time that this one seemed close to ideal, at least for that lot of ammo and how it burned. It doesn't seem to behave as well with the Eley I've tried already, though. The one on the right is somewhere around 30 grams, if I remember correctly. The latter was one that seemed to behave rather well with the lot of Eley Team that I had, and garnered many scores over 2200, including a 2300 and 2350. Something I also managed with a much different one that was only about 14.2 grams.

So if there's only one amount of mass that gets you close to the ideal behaviour why might one see improvements with different amounts of added mass and different ammo? Well, different ammo might have different burn rates for both the primer and the powder. This can change exit times. But we're also talking about harmonics here, not just the fundamental vibration frequency. It is entirely possible that one amount of mass allows you to play with exit times versus the fundamental, and different amounts of mass let you play with exit times versus different swing directions of the different harmonics. While you might find the fundamental's upswing rather easily, you might also be fighting downswings of the various harmonics present.

cantilever-natural-frequencies.png


Image from here, for credit's sake: https://www.mem50212.com/MDME/MEMmods/MEM09155A-CAE/040-Vibration/Vibration.html

Figure B shows what we'd like to affect most. That's the fundamental frequency. But figure C shows the 2nd mode harmonic, and that motion also exists at the same time. And the same goes for the 3rd mode harmonic shown in figure D. And the 4th harmonic, 5th, 6th, etc. They all exist at the same time, with a considerable decrease in amplitude for each one. So maybe a wide range of mass can get you on the right side of the fundamental, but smaller ranges might put you on the good or bad side of the swing of one of the harmonics. I think one of the reasons many people feel tuners aren't helpful and are instead just a different amount of random is because if it isn't a tuner well-matched to the barrel it won't help you out properly with regard to the fundamental, and you may end up playing near the switching of it or one or more of the harmonics, too. Any time you're playing near the time that the barrel is changing directions leads to unstable results. You need the movement to be as stable and predictable as possible in order for it to help you as much as possible. If you're doing a great job of riding a fundamental that's in the right speed range, but you're near where the 3rd harmonic is switching, you'll get worse results. And that's because the portion that the 3rd harmonic is adding to the whole can be enough to negate what the fundamental is contributing. If the fundamental is moving upwards by 5 MOA/ms but the 3rd harmonic is switching up and down by 1.25 MOA/ms then that gives you a range of 3.75 MOA/ms to 6.25 MOA/ms upwards swing, depending on when your shots are exiting with regard to what the 3rd harmonic is doing. If it is such that some shots are leaving while the 3rd is down and some when the 3rd is up then that can be more than enough to make it look like the tuner is doing jack and not helping you at all. (Made up numbers for the sake of example. I haven't calculated how much each harmonic might be responsible for yet, though that should be doable if one were curious about it.) Same goes for the 5th, etc.

They all contribute some amount to the total, and when they occur relative to when shots exit can and do affect things in positive and negative ways. The fundamental is the most important, because it has the most amplitude. Each harmonic has less and less amplitude to contribute, but it all adds up. They all matter. Adding mass like a tuner does dampen things, though. So the addition of any mass at all will tend to calm everything down. And as you go from no added mass and take steps up in mass you'll see regions where it seems to help and regions where it seems to hurt. It all comes down to what all those different harmonics are contributing and how it relates to when shots are exiting. If most of your ammo behaves in a pretty similar fashion with regard to how it ignites and burns then you can use this knowledge to your advantage and get the barrel to help you out. Ammo consistency still matters. It's possible to see different results when doing something like a comparison of Eley to Lapua because they may burn quite differently, resulting in exit times that are quite different. Depending on the barrel design you might be able to tune to the fundamental well enough for both of them to behave rather well. Or they might differ enough that you can't get the barrel to behave in a similar fashion when one exits versus the other. In my case, they seem to differ enough that a setup for one doesn't seem to work as well for the other. One might be in a better space with regard to the fundamental. Or I could be fighting the higher order harmonics. I'm not really sure. For now, all I know is the Lapua seemed to want something in the 100-gram region and the Eley seems to get along in both the 14-15-gram region and ~30-gram region, too. I really hope to get out with the Tenex soon and try to get it dialled in. Bugs me so much that I can't go shooting right now that I may even venture over to the next town half an hour over to use their range at some point, hehe.

(And, yes, at some point I'd like to discuss why those printed tuners are so long.)
 
Thanks for all you are sharing so generously here Shorty.

I have a little bit to add regarding tuner weight. When I started out at this I had no criteria for choosing whether or not to add weight to my Harrell and what to add if I was to add. I settled on shooting 10 shot groups at settings 0 to 500 by 25. I graphed the resultant mean radii vs. setting number. Some weights were better than others and some weights would produce broad smooth curves while others were spikey. I thought broader sweet zones were desirable and believe in this method so far. In my limited experience I would say that you could use this test once on a new barrel and no further weight testing would be required. Not only does it help me pick a weight but also a setting range to test further.

I recognize this is pretty crude compared to your work where you are actually fine tuning the tuner weight.
 
Well, I imagine since this barrel's already done a good portion of the work in getting you near the right ballpark this may be why I've had to play with a much finer amount of weight. It seems to me that the nature of a thicker barrel is going to require more weight to slow it down into the right ballpark, and is likely less sensitive to smaller weight changes as a result. Varmint Al suggested it would likely take a fairly light tuner to get this barrel dialled in, but he didn't really have an idea of what that meant, really. Or, at least, he didn't amplify that statement beyond "it will probably need a fairly light tuner." He didn't say whether or not he also tried modelling a tuner for it in the FEA software when he was working on the barrel's design. But that's the way it looks to me, that a thicker barrel's going to require more mass to affect it, and so smaller changes are probably going to have less effect on it. For example, when helping set up one rifle for a friend he had a weight set for his Harrell that allowed 1-ounce (28.35 grams) increments to be added. Those seemed to be more than enough resolution to play with in order to find the right region. We could see things walking in and out of the sweetspot rather easily as we added an ounce at a time, so if the weight set had been a bit coarser it would likely still have been enough. 2-ounce steps would probably still have been fine in the case of that gun/barrel. 3-ounce steps might have been pushing it.

As for your tuner setup routine, it's kind of similar to the Hopewell method. With that one you shoot 2 shots, spin 25, shoot 2, spin 25, and do that until you have a 10-shot group representing the 0-100 range. Then repeat for 100-200, 200-300, 300-400, and 400-500. Test the entire adjustment range with a single box of ammo spent. Select the group that had the least vertical to proceed with finer testing. At that point, perhaps shoot 2, spin 5, shoot 2, spin 5, and end up with 10-shot groups representing a 25-click region. And select an even finer number of clicks after that. I've done that and it works very well for finding the right region in the total adjustment range. I've also combined that with the two different speed lots idea. For each 2-shot subset I would shoot one from the fast box and one from the slow box. That would tend to make the results even more obvious. You don't have to go crazy. You can achieve good results without diving into it in as much detail, for sure. Diminishing returns likely applies here as much as anywhere else. I certainly don't recommend everyone go out and try to find someone to build a barrel like this when there are world records and championships owed to traditional barrels. I just thought it was a cool idea worth trying at least once, hehe. And since it didn't seem like anyone had done it yet, I figured what the hell. It's been a fun project anyway, and I'm enjoying it. Can't wait to get back out there with it.
 
_Shorty said:
The compensation being spoken of is for muzzle velocity differences. The whole point of getting the barrel in an upswing of a certain rate is so that its upswing rate itself is going to change the angle of departure for every round according to its muzzle velocity. A 1035 fps round needs a departure angle of 10.954 MOA in order to hit zero at 50 yards. A 1075 fps round needs a departure angle of 10.405 MOA in order to hit zero at 50 yards. That's a difference of 0.549 MOA with a difference in muzzle exit time of 0.106666667 milliseconds. That gives a required barrel upswing rate of 5.146875 MOA per millisecond. Which means if you get your barrel so that it is in an upswing of that rate during the period of time when bullets exit it will compensate the amount of departure angle for all shots within a reasonable variation in muzzle velocity.


When even a guy like Bryan Litz decides to run a test to see if tuners work and he comes away with the idea that they don't because he couldn't get any repeatable results it kind of says something about the amount that most people do not know about them and how they work. Essentially, he did the "buy tuner, install tuner, randomly spin it" method of testing them. Since he used (I believe) a CZ 457 for this test, he wasn't exactly using a good rifle, nor a typical benchrest barrel. You pretty much need a barrel that resembles very closely what was used in the design of the tuner you're using or you won't be able to get good results with it. A Harrell tuner weighs a certain amount. And the barrels they're usually installed on are all very typical, similar benchrest barrels. When everybody is using 0.920" 26" barrels (or whatever the most popular dimensions are, that's just a fuzzy guess at remembering) and are getting good results with Harrells on them, it stands to reason that this is exactly what the Harrell was meant to be used on. But taking some CZ factory barrel that's nothing like that and putting the Harrell on it isn't likely to produce any good results. Its vibrational behaviour is just going to be too different from the vastly different benchrest barrels that it was meant to be used on. Might you get lucky and find it helps at some mode? Perhaps. There are a lot of harmonic modes involved, and maybe you'll be able to get some positive results with one of them. But it isn't very likely to be the fundamental mode that you're playing with, because your barrel is just too different from the intended barrel.
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Good lots of ammo, the kind serious RFBR shooters would use for competition can be expected to have relatively small extreme spreads, almost certainly less than 30 fps, probably in the low 20s. Two .22LR match ammo rounds that are 30 fps apart in MV have a vertical difference at 50 yards of about 0.211"; two rounds that are only 20 fps apart will have a vertical difference at 50 of about 0.143". At 50 yards, with small ES and small SD numbers of 5 - 7 fps, there's not a lot of "compensation" for a tuner to achieve. Of course, wide extreme spreads will be too great to be corrected by positive compensation.

With regard to Litz's results testing .22LR with a tuner, they are no doubt representative of tuner testing of a great majority of .22LR shooters who try them. The result is failure (even though many don't in the end admit it, like Litz). The key reason for Litz's failure is not so much the barrel on the CZ rifle he used but the ammo he used -- SK Long Range Match. (The barrel was a straight .900" 1:10 twist 24" Bartlein.)

For a tuner to be effective the ammo must be consistent, not only over the chronograph but also in performance on target -- two things that are not synonymous and are not generally characteristic of SK ammos. In the Litz testing, the SK ammo was randomly selected, not the product selection by careful lot testing. Using this ammo would doom or significantly impair successful tuner testing. Clearly, Litz doesn't understand .22LR well.

Anyone like Litz who relies on entry level .22LR match ammo such as SK to find a reliable tuner setting can expect inconsistent and unverifiable results -- in other words, failure. It shouldn't be a surprise if those who try and fail rarely post about it. Indeed, the fact that many shooters insist that their tuners work at all distances without readjustment, including beyond 100 and 200 yards, suggests that their tuners work more as a confidence builder than anything else. No doubt many continue to mistakenly see tuners as a solution to solve the problem of inconsistent .22LR ammo. The use of tuners for long range shooting is much more challenging because of the many causes for ammo performance uncertainty, unless, of course, it's possible to calculate on paper beforehand what's required.
 
1:10 twist? Are you sure? I couldn't find an equipment specification anywhere for his test, but if that's not a typo, it is very strange. Someone accidentally buy a .223 barrel and chamber it for 22 LR? Haha. If it really was 1:10 that's basically a Mini-14 replacement barrel. Failure right there with the wrong bore diameter, because a .22 LR bore is tighter than .223 bore. A .22 LR bore should be 0.217" with 0.222" grooves, and a .223 Remington / 5.56 mm bore should be 0.219" with 0.224" grooves. Nearly all .22 LR barrels are 1:16 twist, with some manufacturers/people trying 1:16.5 and getting good results. If he did actually have a 1:10 twist barrel there's no doubt in my mind it was a .223/5.56 mm barrel and would not shoot worth a damn no matter what you did. It was likely barely sealing properly from being too large. Skipping back and forth through the first few minutes of the podcast discussing the test confirmed it was a 24" Bartlein, but I didn't find any mention of twist rate or contour. While trying to find an article (and failing) rather than a podcast I did run across a bunch of forums discussion on the test, and someone said he was testing at crazy weight intervals, like, a pound at a time. He was clearly stumbling around in the dark on that one. SK Long Range Match? Yeesh.

The guys on the Hornady podcast did their own fair share of stumbling around in the dark when they talked about it, too. It would be great if people like this could share some range time with some of the good ARA shooters that clearly know how to dial in their equipment to demonstrate exactly what's going on so that such high profile people don't continue to add to the pool of ignorance on the subject. They're clearly smart guys who did poor research ahead of time and didn't know how to approach the problem during their testing and got incredibly poor test results because of it.
 
Barrel makers are making .22 LR barrels in all sorts of twist rates these days. 1:9, 1:10, 1:12, 1:14 and everything in between I would guess. Trying to find that unicorn barrel that performs at long range and sell it to the PRS crowd.
 
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Walterfisher said:
Barrel makers are making .22 LR barrels in all sorts of twist rates these days. 1:9, 1:10, 1:12, 1:14 and everything in between I would guess.
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No point with match ammo all having 40-grain bullets. All the competitive (and match winning) barrels are 1:16 or 1:16.5 twist because that's the right range for the 40-grain bullets. Going faster than that is detrimental. The reason some people tried 1:16.5 was because they had an inkling that 1:16 might be just a little too fast to wring every last drop out of them. And some of them saw slightly better results slowing it down a tad like that. Going faster never saw any gains, and only made things worse, and similar results when going to 1:17 or slower. The optimal spot seems to be somewhere in that 1:16 to 1:16.5 range. I believe all Benchmark's standard barrels are 1:16.5 now. Or, at the very least, that's all that Gary seems to bring into Canada.
 
_Shorty said:
No point with match ammo all having 40-grain bullets. All the competitive (and match winning) barrels are 1:16 or 1:16.5 twist because that's the right range for the 40-grain bullets. Going faster than that is detrimental. The reason some people tried 1:16.5 was because they had an inkling that 1:16 might be just a little too fast to wring every last drop out of them. And some of them saw slightly better results slowing it down a tad like that. Going faster never saw any gains, and only made things worse, and similar results when going to 1:17 or slower. The optimal spot seems to be somewhere in that 1:16 to 1:16.5 range. I believe all Benchmark's standard barrels are 1:16.5 now. Or, at the very least, that's all that Gary seems to bring into Canada.
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The theory, as I understand it, is that the faster twist barrels give up some gains out to 100 yds/m but see some gains past 200 yds/m. There is no current data or scientific experiments to prove this that one can access, so I remain unconvinced. However, most barrel makers now will give you a 22 LR barrel in whatever twist rate you request and some will even do a gain twist.
 
Walterfisher said:
The theory, as I understand it, is that the faster twist barrels give up some gains out to 100 yds/m but see some gains past 200 yds/m. There is no current data or scientific experiments to prove this that one can access, so I remain unconvinced. However, most barrel makers now will give you a 22 LR barrel in whatever twist rate you request and some will even do a gain twist.
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Ah, maybe you've got something there with long distance shooting. Maybe during all that flight time there's enough drag to actually begin slowing down in RPM by a meaningful amount, and a faster start can make up for it. I haven't really looked into that side of things with 22 LR at all. I'm mostly a 50-yarder, hehe. (And silhouette, baby! haha) I'm with Krieger on the gain twist, though. I don't like the idea of it because you're cutting grooves that change in width, which will probably affect seal, potentially introducing some inconsistency. And it doesn't really seem to provide any benefit.
 
_Shorty said:
1:10 twist? Are you sure? I couldn't find an equipment specification anywhere for his test, but if that's not a typo, it is very strange.
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Using fast twist barrels is quite fashionable and popular these days, especially with PRS shooters. It may be a perceived solution rather than a real one. There is no reliable published data supporting improved results with fast twist barrels, but many who shoot PRS-style see it as the solution to uneven .22LR ammo performance. The proponents claim that faster twist barrels improve .22LR bullet BC which is supposed to result in better performance at longer distances.

Perhaps like tuners for long distance performance improvement, PRS-style shooters are looking for a technical quick fix to improve the performance of .22LR ammo, performance which inevitably gets worse as distance grows.

In any case, in his 2022 book Modern Advancements in Long Range Shooting, Volume III, Litz says the rifle used has a 1:10 twist barrel.

 
Ah, he mentioned it there, ok. Thanks for that. That tuner shown there weighs about 6 ounces, and a Harrell weighs about 9 ounces. People getting good results with a Harrell on a 0.920" barrel says to me that perhaps 6 ounces on a 0.900" barrel isn't in the right ballpark. It would sure be nice if he could revisit a test like this with a really successful benchrest shooter, someone that's had lots of good results in ARA. Gotta be more than a few near him. Oh well.

Whether fast twist rates improve BC should be rather easy to test. Just need a LabRadar. Well, and such a barrel. On that note, it seems roughly 5% of even Tenex rounds have a BC that's way outside. Ain't nothin' perfect, hehe.
 
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