I have one but havent been able to really test it yet. Ammo shortage and weather has made it difficult.PVA is offering a 12 twist barrel for Rim X actions. Anybody try one of these yet?
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I have one but havent been able to really test it yet. Ammo shortage and weather has made it difficult.PVA is offering a 12 twist barrel for Rim X actions. Anybody try one of these yet?
Just got one- so far, good at 50 and 100-( meaning the same results as my Proof 20" CF 16twist with lot tested CX and SK Long Range) I am trying it at 200 this week. will report back.PVA is offering a 12 twist barrel for Rim X actions. Anybody try one of these yet?
I spoke to John at LW who makes those and recommended the barrels be counterbored under the muzzle threads. Does yours have that done?The PVA 1 to 12 shot about the same as my Proof 1 to 16 at 200. 20 round 4" groups outdoors wind about 5mph. ( SK rifle match and Center X). Since 99% of my shooting will be 200 or less, that's fine. One NRL match at our club will be out to 400 next year. I'll test it further out before that. I could lot test and get better results, just shot what i had from my other barrel.
Wow, that's a massive improvement.So what Mike talked about what got me was the BC improvement from .130 to 0.170.
Please gather some data, this aspect is very interesting. Because practically the best BC should determine the best twist.Mine shoots flatter enough to notice
Please gather some data, this aspect is very interesting. Because practically the best BC should determine the best twist.
I cannot be the only one who cares about this.
The problem is that data suggests faster twist causes greater dispersion from small-scale imbalances in the bullets, tiny misalignments, etc.
When was the "standard" 16 twist developed for rimfire ? And a follow up to this, what was the quality of projectile then VS what The quality is like now ?
Perhaps this is why twist rates are being revisited and new research is being done.
Exciting time to be alive.
Interesting read. I've been messing with 35cal stuff for a while and recently changed from 7.5 to 8.5 twist, which I'm still awaiting for delivery. This explains what's happening to me. Good to see I'm 18months behind the curve.
This is a different world at the velocities a 22 is going. Maybe when the weather warms up, I’ll put these barrel to the test with some lead ammo. I have a 22.5” and 28” 1-5.75 twist barrels and a 28” 1-6.5. They weren’t for lead to begin with but I do enjoy a good testThis is from the supersonic world, but @Jim Boatright and David Tubb needed to dial back the twist from 1:6.6 to 1:8 on a 338-caliber on an experimental rifle a year ago because with modern monolithic projectiles it was getting 0.75 MOA groups at best on a 105yd indoor range.
Correction: it was due in part to substantial yaw encountered in the muzzle blast, and due in part (as shown at longer distances) to extremely variable time of flight with 4fps extreme spread at the muzzle.
Post is here: https://www.snipershide.com/shooting/threads/progress-in-developing-copper-uld-bullets.6973906/
I have both made 6DOF tests and asked a skilled ballistician about 16 vs 9 twist. What he found out is that while 9 twist should be too much and create problems, 13-15 twist is good. According to his simulations 22LR becomes unstable around 1:20".The problem is that data suggests faster twist causes greater dispersion from small-scale imbalances in the bullets, tiny misalignments, etc.
Its very much a balancing act, and fundamentally, known elevation is trivial to dial for, while unknown dispersion isn’t. You’re effectively trading a reduction in unknown windage for an increase in unknown dispersion.
Doing better in thick cold air and wind... that means an increase in BC if nothing else changed but the bullet rpmI got very much help from a ballistician when I asked him about 16 vs 9 twist.
I have both made 6DOF tests and asked a skilled ballistician about this. What he found out is that while 9 twist should be too much and create problems, 13-15 twist is good. According to his simulations 22LR becomes unstable around 1:20".
Sg of 1.5 should have the optimum (read: enough to now encounter problems in different situations) amount of twist for the bullet.
1:16" 20C 0mph 300m Sg=1.26 at muzzle
15.71U 0.2R (Spin drift)
1:14" 20C 0mph 300m Sg=1.54 at muzzle
15.71U 0.23R (Spin drift) -- 0.03mil difference to 16"
10mph wind:
1:16" 20C 10mph 300m
15.88U 3.44R (Spin drift + Wind)
1:14" 20C 10mph 300m
15.89U 3.46R (Spin drift + Wind) --- 0.01 and 0.02 difference to 16". But 6DOF predicts that 14" will have 0.0003 seconds faster flight time.
Below are calculations for cold weather, MV was kept the same to make data easily comparable, but in reality the elevation would be a lot more.
But because the MV would be lower, so would the Sg numbers (Stability) drop. But fortunally velocity has quite small effect on it. As on the other hand, a lower MV will induce less drag for the bullet, making it deflect less by the wind.
1:16" -25C 0mph 300m Sg=0.98 at 6m from the muzzle, Lapua self-corrected to this distance. My guess is around 0.92.
17.14U 0.23R (Spin drift)
1:14" -25C 0mph 300m Sg=1.28 at 6m from the muzzle, Lapua self-corrected to this distance. My gues is around 1.22.
17.14U 0.26R (Spin drift) --- 0.03R difference to the benefit of 16" twist
10mph wind:
1:16" -25C 10mph 300m
17.68U 4.47R (Spin drift + Wind)
1:14" -25C 10mph 300m
17.31U 4.31R (Spin drift + Wind) --- 0.37U and 0.16R difference to the benefit of 14" twist.
So clearly, 14" will do better when it is cold and windy. I am not sure but according to my findings and modeling work done by a pro ballistician, it seemed that 13-15" is where the bullet flight will be the least problematic in some areas.
I am not sure why but it seems 22LR seems to do fine with 16 twist and improving the twist has only one effect according to 6DOF:
The bullet will be cutting dense air and wind better at longer distances, without any negative side effects (0.02-0.03 mil is not enough to matter really, when the 1:16 will have 0.4mil+0.15mil variance added to POI by 10mph wind.
But even for the calculations I did myself (ballistician had his own software for the simulations) the Lapua 6DOF bullet profile cannot be 100% true, according to ballistician they must have have set some values regarding stability by hand.
As for myself, I do not know how tight one should go. But I guess that a longer barrel will provide smoother MV ES (info from padom) and also reduce muzzle blast that can give a bullet 1) bad flight 2) angular momentum into a wrong direction.
And I do not believe that 1:14" would turn anything upside down, as even Anschutz has offered them at some point.
Most important is that the barrel is carefully made, both chamber and lapping.
Enjoying reading this thread. I'd be interested to hear if the faster twist rate barrels make any difference for non ELR shooting, at 100 metres/yards compared to normal 1:16"/1:16.5" twist barrels. My rifle shoots nice tight groups with holes touching at 50m but going out to 100 yards the groups triple in size. I'd like to know if a faster twist barrel but used with standard, subsonic, lead bullets can improve things at 100? Thanks and keep the updates coming
This is from the supersonic world, but @Jim Boatright and David Tubb needed to dial back the twist from 1:6.6 to 1:8 on a 338-caliber on an experimental rifle a year ago because with modern monolithic projectiles it was getting 0.75 MOA groups at best on a 105yd indoor range.
Correction: it was due in part to substantial yaw encountered in the muzzle blast, and due in part (as shown at longer distances) to extremely variable time of flight with 4fps extreme spread at the muzzle.
Post is here: https://www.snipershide.com/shooting/threads/progress-in-developing-copper-uld-bullets.6973906/
How do such barrels compare with standard twist barrels in terms of group size at 100 yards? (I refer to 100 yards because at longer distances such as 200 yards and more it becomes increasingly difficult to account for all the variables that make group sizes inconsistent at such ranges.)Yessir, I finalized the testing over two years ago....Nine twist at least 22" long is the way to go.
MB
The 25 and 50 yard groups are the exact same and you start to see a slight improvement at 100, but the faster twist really starts to shine beyond that. I called wind for three days with nine and 16 twist guns side by side in the hands of over 300 shooters and data logged the results at 276 and beyond. The results were pretty incredible.How do such barrels compare with standard twist barrels in terms of group size at 100 yards? (I refer to 100 yards because at longer distances such as 200 yards and more it becomes increasingly difficult to account for all the variables that make group sizes inconsistent at such ranges.)
Have any Vudoo rifles with such barrels been made or ordered?
For standard 40gr. lead bullets used in common match offerings?Yessir, I finalized the testing over two years ago....Nine twist at least 22" long is the way to go.
MB
Yessir, the new Cutting Edge Bullets will be a little different.For standard 40gr. lead bullets used in common match offerings?
So the 1:12 wasn't as effective as 1:9?Yessir, I finalized the testing over two years ago....Nine twist at least 22" long is the way to go.
MB
Thank you.The 25 and 50 yard groups are the exact same and you start to see a slight improvement at 100, but the faster twist really starts to shine beyond that. I called wind for three days with nine and 16 twist guns side by side in the hands of over 300 shooters and data logged the results at 276 and beyond. The results were pretty incredible.
Yessir, we've taken orders for and built nine twist guns.
MB
The reason for going down the path of faster twist barrels is based on the difference between published BC and actual data based on what we see in our ballistic solvers when we align what we see downrange....they don't match. The TOF data at 100 yards using a 16 twist barrel consistently calculated BC at .120-ish, which aligns with the number we use so things line up properly in our solvers.So the 1:12 wasn't as effective as 1:9?
What is the procedure to order just the barrel? and can i replace it myself?
I have no idea other than to surmise that maybe the data either wasn't attainable in the way we can derive it these days or maybe what was seen in performance was well inline with the application at the time.Thank you.
An obvious question that comes to mind is one that you may not be able to answer. If faster twist barrels are the same as standard out to 50 and show "a slight improvement at 100" why would firearms makers have made the vast majority of .22LR rifles in standard twist for about a century?
A second question is about the comparison of the data logged between nine and 16 twist rifles. Will it be made public, perhaps reproduced in a forum?
As anecdotal reports are not reliable, I look forward to seeing whatever data is made available.I have no idea other than to surmise that maybe the data either wasn't attainable in the way we can derive it these days or maybe what was seen in performance was well inline with the application at the time.
I'll discuss a portion of it openly here, but there are parts of it I won't talk about just yet. I'm not trying to hide anything or keep useful info all to myself, as it will be made public at some point soon. But, posts like this have to be managed closely and my time to be available for the coming weeks will be sporadic.
MB
Looking forward to more details when this time is right.The 25 and 50 yard groups are the exact same and you start to see a slight improvement at 100, but the faster twist really starts to shine beyond that. I called wind for three days with nine and 16 twist guns side by side in the hands of over 300 shooters and data logged the results at 276 and beyond. The results were pretty incredible.
Yessir, we've taken orders for and built nine twist guns.
MB
Is there going to be a common twist and chamber for 40gr sub ammo and the new cutting edge bullet? If there was a compromise Magazine/chamber/twist/barrel-length/for both, what is the performance cost?Yessir, the new Cutting Edge Bullets will be a little different.
MB
I think the point for the 32gn bullet was to fit in a standard mag and work well with standard chamber/twist. Personally, I am interested in them for hunting (here in a lead free state). Also, the lower BC is offset by the higher velocity, and supposedly they are designed to transition to subsonic well.The BC is so low on the 32 what is the point? Maybe can create a more consistent load?
They just released a preliminary list of tested powders for the 32gn bullet, there are quite few options.Wonder what powder and how many grains work?
The recently published the testing results they did. Here is the image. This was on the 32 grain bullets. 1:16 twistsWonder what powder and how many grains work?
I think the point is to have a bullet that can be used by everyone who doesn't have a faster twist barrel. Whether it's worthwhile is a good question.The BC is so low on the 32 what is the point? Maybe can create a more consistent load?
Just waiting for them to arrive on my doorstep.No one knows until these are live and we have been able to work with them. But if you can shoot a 32gn pill at 1600fps that will be significantly flatter than a 40gn pill at 1080fps (close to 10 feet different at 300 yards), and it would still be supersonic at 100 yards.
Will the lower BC/greater wind drift offset this? Will it really transition to subsonic gracefully? Can you really run it successfully at 1600fps? 1450 fps?
Or even more basically, will the quality of the primed brass be good enough to get enough usability/consistency to realize any benefits at all?
But it sounds like it will be fun to try
At 1650/1700 fps it’s ain’t that low...The BC is so low on the 32 what is the point? Maybe can create a more consistent load?
If anybody knows, it’s this guy.This is a cool topic and BigJimFish is touching on a few things of importance as it relates to Rimfire ELR (used to be an oxymoron). I've been testing faster twists for nearly two years and the results have been pretty awesome. The cool thing is, I'm getting the same performance relative to group size at 50 yards as my 16 twist guns are producing, but I see much tighter groups beyond 100 yards.
MB