Only when I quoted your post did my post go up for moderation... I think the 'system' holds random posts for random reasons, there was nothing wrong with your post.
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FT & JSB 13.43's?
- Thread starter mwgm2020
- Start date
Very cool and appears to support two things i've been hearing a lot of recently. The poly barrels are amazing and 20cal has a killer BC.< 20fpe BC comparison
@Arzrover did some extensive ballistic coefficient testing and posted his results in the projectiles section. https://www.airgunnation.com/threads/difficult-choices.1282745/ Just wanted to share it here since it's so relevant for field target and perhaps some ft diehards only follow the FT...www.airgunnation.com
Too bad the latest LW 20's have been throwing 1" groups at 30 yards.
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No risk at all if max velocity is a few fps below 818 and having a high ES will actually reduce the risk of shooting hot... If your ES is high your average velocity will be much lower than your highest velocity when compared to a lower ES. Since the maximum velocity is several fps below 20 ft-lbs (818.8) you'll never pop over 20 ft-lbs let alone 20+2% unless heat is a factor and then you have 20fps or more to play with.
I have 177 barrels where there is a difference between 800 and 815 for 13.4's. One likes the pellets as fast as you want to send them, the other looks like it is corkscrewing when the velocity goes above 800. The longer barrel is tending to corkscrew at speed.
If you run 22cal you'll see improved velocity above 800, 810, 820, 830, 840...until you get to 890, so they need to run right up against the velocity limit to be as accurate as possible. With an unregulated rifle things get tricky and the risk is higher, but for regulated rifles the velocity curve is essentially flat and the risk is minimized. This is the only use case where you'll need to run a risk of shooting hot because the 13.4 22's like more speed than FT rules allow.
I actually lost a match because I was complaint with the speed limit and the other person (also shooting 22) shot over the speed limit and did not get disqualified... We were sitting next to each other on the sight in line and he kept saying how amazingly accurate his rifle was and I knew he was overpower. I knew because I was seeing better accuracy and I was overpower, I detuned before the match and the other person did not (this was before the 2% rule). Those pellets loved that extra 10fps and the gain in accuracy was significant.
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Yes, and yes.
1:36 slow twist poly with .177/10.34s at 920ish, or .20/13.73s @ 800ish. Both are mui bueno.
One possible option is to repurpose one....the .20 barrel in my USFT was originally in an Air Force Condor. Yes, still LW, but perhaps AF orders them spec'd differently or something. Or perhaps it's just as simple as barrel to barrel variation and I got lucky to find a good one.
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In regards to the adjacently related 2% rule....best to stay under the actual legal limit and not rely on that 2%.
Risky business relying on the 2%. It exists because of chrono variation, and variation is something notoriously seen from different chronos, even the same model.
Risky business relying on the 2%. It exists because of chrono variation, and variation is something notoriously seen from different chronos, even the same model.
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Wow, a wealth of info here to slowly go thru and digest. I typically just shoot and whichever is the most accurate run with it. I will say, none of my guns will shoot a 13gr pellet to 55yds though. They all spiral and several are well known platforms for others using them.< 20fpe BC comparison
@Arzrover did some extensive ballistic coefficient testing and posted his results in the projectiles section. https://www.airgunnation.com/threads/difficult-choices.1282745/ Just wanted to share it here since it's so relevant for field target and perhaps some ft diehards only follow the FT...
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Well i've been shooting FT since 2011 and haven't shot hot yet and most of those years were before the 2% rule using an unregulated USFT.
During that same time I have only seen one chrony be off by more than a few fps and it was a ShootingChrony, it was off by 40fps (it was mine).
I have also seen people shoot too fast and too slow recently because they did not run their rig over the match chrony (or use their own) prior to the event. In fact I saw six people do this at the last event.
Don't worry about my velocity, worry about yours.
During that same time I have only seen one chrony be off by more than a few fps and it was a ShootingChrony, it was off by 40fps (it was mine).
I have also seen people shoot too fast and too slow recently because they did not run their rig over the match chrony (or use their own) prior to the event. In fact I saw six people do this at the last event.
Don't worry about my velocity, worry about yours.
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Yep, Thomas #1 with a 15" poly loves the 13.4's at speed, Thomas #293 with an 18" poly loves the 13.4's at a velocity at or below 800 (780) and they start to visually spiral over 820 (at 810 you can see the group size open up).
I took two 24" 177 barrels that shot great on a USFT and put them in Thomas #1 and couldn't get anything for results.
Thomas #1 did not like 10.34's at 20 ft-lbs but is a serious shooter with 10.34's at 12 ft-lbs.
I'm beginning to wonder if I swapped the barrels on my two Thomas' would they shoot the same...?
Thomas #1 is a totally different rifle than #293.
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I apologize. You seem to have taken affront with my generally intended comment about the velocity. I don't know you and have no idea about how hot you like to run your gun. No insult or slight was meant by my comment. Again, just a general cautionary advisement.
I saw a variation of 50 feet per second one day, from three different chronographs, one was shooting chrony, one was that little deal that hangs on the barrel, and one was a Labradar. The 2% exists for that reason.
Keep it under 20fpe, without relying on the 2%, and it won't be a problem when the match directors chrony reads 20fps hotter than our personal chrony. That's all.
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It wasn't just you Frank, several people seem overly concerned about he way I run my setup... I can only imagine they have a few GP and Nationals championships in their award cabinets... 
If a match chrony is shooting 50fps off (hot) it is far better to check your equipment over the match chrony than to worry about the 20 ft-lb tune. 50fps is 33fps over the 2% add so to no shoot hot using that chrony you would have to be tuned to 785 to pass (using 13.4's). So that 20 ft-lb tune with a bit of headroom (800 to 810fps) is too hot and is now disqualified.
17fps is the lee way so even a 20fps hot match chrony can make a bad day.
I'm religious about knowing the match chrony velocity on match day just in case the match chrony is junk.
And my maximum velocity for the entire shot string is 818. Sounds like its running under 20 ft-lbs to me... And with three tries and only one shot at 818 in the string, well yeah, not an issue, ever.
If a match chrony is shooting 50fps off (hot) it is far better to check your equipment over the match chrony than to worry about the 20 ft-lb tune. 50fps is 33fps over the 2% add so to no shoot hot using that chrony you would have to be tuned to 785 to pass (using 13.4's). So that 20 ft-lb tune with a bit of headroom (800 to 810fps) is too hot and is now disqualified.
17fps is the lee way so even a 20fps hot match chrony can make a bad day.
I'm religious about knowing the match chrony velocity on match day just in case the match chrony is junk.
And my maximum velocity for the entire shot string is 818. Sounds like its running under 20 ft-lbs to me... And with three tries and only one shot at 818 in the string, well yeah, not an issue, ever.
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Math and science are great and all, but I would encourage you to deviate from the theoretical. Next time your are practicing with some wind, shoot 7.9s, 8.4s, 10.3s and 13.4s at a target. I won't spoil it for you, but you will learn something.
You have control over your vertical hold (if you've done your homework). You don't have control over wind. I'm more confident in my ability to hold 2.5 mil over on a close target than I am in determining if the wind halfway to a long target is 3 mph or 6 mph.
I will always pick the heaviest pellet that a gun will shoot, and if it won't shoot 13.4s, I'll use a gun that will. Unless I'm shooting WFTF or a springer, then it's 8.4 all day.
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Mostly because I have 2 sleeves of 8.44, but also because I've shot 8.44 at 12 foot pounds for 10 years, so I'm familiar with the behavior. And I've only had one springer that likes the 10.3s, but I don't shoot that gun very often.
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I have only shot two matches in WFTF (one club match about ten years ago with an EdGun and the 2024 Worlds in Arizona), I was using 10.34's at the Worlds simply because they shot better than the 8.44's out of that particular barrel.
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Because I assumed the longer, heavier 13.43s have a higher B.C. than 10.3s, I consider B.C. the most important quantification of resistance to wind drift, 13.4s return more energy in Hunter Class rifles, and that advantage increases with distance. However, having just checked JSBs own B.C. chart I see there is no B.C. difference between 10.3s and 13.43s. So I (might) stand corrected.
Which introduces the question- other than if they are more accurate in One's FT rig, why would anyone use 13.43s in field target?
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I wholehearted declare "maybe".
It would have opened quite a 
of 
, and AAFTA is allergic to worms!Slugs having huge wind-drift advantages over pellets, the only practical option for AAFTA would have been adding a Slug division; which might (then) entail doubling the number of AAFTA classes (Slug Hunter, Slug Open, Slug WFTF, Slug Unlimited).
Reasons not to do that are several. 1) Considerably greater toll on targets. 2) Requiring higher Troyer targets for Slug shooters. 3) Requiring more distance between targets and surrounding neighbors. 4) Consequently larger FT venues. 5) That's enough (but there are probably more).
By the way, the reasons above are why I started a Slug class in my quarterly TEXtreme Bench-Rest Silhouette competitions held at the local FIREARMS club, but not my TEXtreme Field Target matches held on my 30 acre home-place (with neighbors close by).
The airgun BRS Slug shooters not only ALWAYS posting higher scores than the pellet shooters, but comparable scores to the RIMFIRE BRS shooters is indisputable proof-positive of slug superiority over pellets in real wind conditions.
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It also exists because the cheater that had been shooting over the limit because he didn't want to go to the trouble of tuning his gun to legal limits sold the 2% wiggle-room BS to the BoG, and they bought it. These are historical facts.
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I’ve tested a variety of 10.x gr, 13.4gr and my two 20ft-lb FT rifles prefer 13.4 original monster profile.
I don’t care as much about small improvements in trajectory as I do minimal flyers at 45-55y.
Slugs are cool but would be unsafe in many locations, such as my club.
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