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Posted: 7/11/2015 9:27:46 PM EDT
[#1]
Quoted:
Are A2 20" profile barrels made in both twist rates? Thank you Bushmaster makes (or made) a 1/9 twist. I would stick with 1/7, more versatile |
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Posted: 7/11/2015 10:07:47 PM EDT
[#2]
Thank you
So If I find one good chances are its 1/7? |
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Posted: 7/11/2015 10:10:51 PM EDT
[#3]
Quote HistoryQuoted:
Thank you So If I find one good chances are its 1/7? Yes, some may be 1/8 as well |
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Posted: 7/11/2015 10:16:47 PM EDT
[#4]
Quote HistoryQuoted:
Yes, some may be 1/8 as well Quote HistoryQuoted:
Quoted:
Thank you So If I find one good chances are its 1/7? Yes, some may be 1/8 as well 1/8 for best overall twist IMHO. |
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Posted: 7/11/2015 10:24:10 PM EDT
[#5]
So who makes a 1/8 twist 20 inch A2 barrel?
Never seen one. |
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Posted: 7/11/2015 10:28:04 PM EDT
[#6]
what weight rounds do you shoot? Do you just shoot 55gr stuff or do you shoot heavier?
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Posted: 7/11/2015 10:29:26 PM EDT
[#7]
Quote HistoryQuoted:
So who makes a 1/8 twist 20 inch A2 barrel? Never seen one. Green mountain http://www.gmriflebarrel.com/gm-m16-m16a2-5-56mm-20-barrel-with-extension-1-8-twist/ |
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Posted: 7/11/2015 10:31:43 PM EDT
[#8]
Quote HistoryQuoted:
what weight rounds do you shoot? Do you just shoot 55gr stuff or do you shoot heavier? Mosty 50-62 grains for range practice trips |
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Posted: 7/11/2015 10:32:51 PM EDT
[#9]
Quote HistoryQuoted:
Green mountain http://www.gmriflebarrel.com/gm-m16-m16a2-5-56mm-20-barrel-with-extension-1-8-twist/ Quote HistoryQuoted:
Quoted:
So who makes a 1/8 twist 20 inch A2 barrel? Never seen one. Green mountain http://www.gmriflebarrel.com/gm-m16-m16a2-5-56mm-20-barrel-with-extension-1-8-twist/ Thank you Do they sell one with a FSB? |
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Posted: 7/11/2015 10:54:53 PM EDT
[#10]
Quote HistoryQuoted:
Thank you Do they sell one with a FSB? Quote HistoryQuoted:
Quoted:
Quoted:
So who makes a 1/8 twist 20 inch A2 barrel? Never seen one. Green mountain http://www.gmriflebarrel.com/gm-m16-m16a2-5-56mm-20-barrel-with-extension-1-8-twist/ Thank you Do they sell one with a FSB? No, and i dont think anyone else does |
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Posted: 7/11/2015 11:00:04 PM EDT
[#11]
Thanks zackmars
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Posted: 7/11/2015 11:06:33 PM EDT
[#12]
Quote HistoryQuoted:
Mosty 50-62 grains for range practice trips Quote HistoryQuoted:
Quoted:
what weight rounds do you shoot? Do you just shoot 55gr stuff or do you shoot heavier? Mosty 50-62 grains for range practice trips Weight doesn't matter, length does. 1/7 can stabilize almost anything, except super short and lightweight varmit rounds, like 36-45 gr. The palmetto 50 gr varmit ammo from federal does great in any twist (though i don't know how well it does past 100 yards in 1/7) And m193 is good to about 200 yards 1/7 is great for longer bullets, like 77gr otm's that are becoming more popular. If you plan on shooting nothing but 55~ gr ammo, 1/9 and 1/8 are great choices, but 1/7 can better handle some really awesome projectiles |
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Posted: 7/11/2015 11:13:40 PM EDT
[#13]
Thanks for that info.
I'd like to be able to shoot a wide range of ammo except the really light stuff |
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Posted: 7/11/2015 11:23:16 PM EDT
[#14]
Quote HistoryQuoted:
Thanks for that info. I'd like to be able to shoot a wide range of ammo except the really light stuff No problem! Since the a2 "spec" calls for a 1/7, that will be the most common, but you will be served well by either 1/8 or 1/7. |
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Posted: 7/12/2015 8:25:57 PM EDT
[#15]
I will look for 1/7' then
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Posted: 7/15/2015 8:27:26 PM EDT
[#16]
Quote HistoryQuoted:
Bushmaster makes (or made) a 1/9 twist. I would stick with 1/7, more versatile Quote HistoryQuoted:
Quoted:
Are A2 20" profile barrels made in both twist rates? Thank you Bushmaster makes (or made) a 1/9 twist. I would stick with 1/7, more versatile This is a myth. A non-truth. Based only on the fact it's what the mil is using. 1/7 was required for the tracers. That's it. If you're not shooting tracers or the really freaky super heavy for caliber loads, threre is no point in 1/7 at all. The mil found 1/7 to be much less accurate than the 1/9 barrels. Further, the faster twist and friction causes the barrel to wear faster as well. Neither is a "better" or "versatile" characteristic. |
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Posted: 7/15/2015 8:58:15 PM EDT
[#17]
1:7 can shoot quality 55gr bullets very accurately
1:7 can also shoot 77gr HPBT with are great for long range accuracy, and superb for terminal effect. 1:9 cannot usually stabilize 77gr bullets make mine 1:7 every time. 
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Posted: 7/15/2015 9:03:01 PM EDT
[#18]
Quote HistoryQuoted:
This is a myth. A non-truth. Based only on the fact it's what the mil is using. 1/7 was required for the tracers. That's it. If you're not shooting tracers or the really freaky super heavy for caliber loads, threre is no point in 1/7 at all. The mil found 1/7 to be much less accurate than the 1/9 barrels. Further, the faster twist and friction causes the barrel to wear faster as well. Neither is a "better" or "versatile" characteristic. Quote HistoryQuoted:
Quoted:
Quoted:
Are A2 20" profile barrels made in both twist rates? Thank you Bushmaster makes (or made) a 1/9 twist. I would stick with 1/7, more versatile This is a myth. A non-truth. Based only on the fact it's what the mil is using. 1/7 was required for the tracers. That's it. If you're not shooting tracers or the really freaky super heavy for caliber loads, threre is no point in 1/7 at all. The mil found 1/7 to be much less accurate than the 1/9 barrels. Further, the faster twist and friction causes the barrel to wear faster as well. Neither is a "better" or "versatile" characteristic. You say 1/7 being more versatile is a myth, then say 1/7 is less accurate and doesn't last as long as 1/9 
Oh the irony |
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Posted: 7/25/2015 7:12:59 AM EDT
[#19]
Quote HistoryQuoted:
You say 1/7 being more versatile is a myth, then say 1/7 is less accurate and doesn't last as long as 1/9
I did. And it's not an opinion, it is a mil researched fact. So your point was? |
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Posted: 7/25/2015 7:38:05 AM EDT
[#20]
Quote HistoryQuoted:
I did. And it's not an opinion, it is a mil researched fact. So your point was? Quote HistoryQuoted:
Quoted:
You say 1/7 being more versatile is a myth, then say 1/7 is less accurate and doesn't last as long as 1/9
I did. And it's not an opinion, it is a mil researched fact. So your point was? The military found out that 1/9 sucked for longer, and heavier bullets Guess what? They were right. 1/7 can stabilize anything from 50 grains to 80 Grains 
I'll humor you position How much are you shooting to a, notice the barrel life, and b, care about the cost of a new barrel Also, the biggest killer of barrels is heat, not twist rate 
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Posted: 7/25/2015 7:54:43 AM EDT
[#21]
Quote HistoryQuoted:.....
1/7 was required for the tracers. That's it. If you're not shooting tracers or the really freaky super heavy for caliber loads, threre is no point in 1/7 at all. The mil found 1/7 to be much less accurate than the 1/9 barrels. Further, the faster twist and friction causes the barrel to wear faster as well. Neither is a "better" or "versatile" characteristic. dated incorrect gun magazine propaganda ...and yes, we like to shoot "really freaky super heavy" 77gr bullets. cranked out in batches of 1000 on my DILLON machine. tracers are fun too. My 1/7 barrels shoot 55gr VMAX like a fucking lazer There is a reason that the top notch brands use 1/7 Colt Noveski BCM Daniel Defense etc. |
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Posted: 7/25/2015 11:12:08 AM EDT
[#22]
You can always get a gm barrel and hv john thomas install a fsb.
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Posted: 7/25/2015 7:46:37 PM EDT
[#23]
Quote HistoryQuoted:
I did. And it's not an opinion, it is a mil researched fact. So your point was? Quote HistoryQuoted:
Quoted:
You say 1/7 being more versatile is a myth, then say 1/7 is less accurate and doesn't last as long as 1/9
I did. And it's not an opinion, it is a mil researched fact. So your point was? And of course you're willing to cite your source on this researched fact, yes? I'm curious, not casting aspersion, except perhaps that you're arguing from authority without citing it. Especially after Molon posted a test result in the ammo forum showing zero-to-negligible difference in accuracy between 1/7 and 1/9 twists, using identical ammunition. |
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Posted: 10/6/2015 9:45:02 PM EDT
[#24]
My A2 is a 1/9 twist.
Shoots 75 grainers very well. But 99% of my ammo is 55 grainers. So, for me the 1/9 is just fine. 
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Posted: 10/6/2015 10:45:28 PM EDT
[#25]
1/9 for me. ymmv
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Posted: 10/7/2015 3:22:16 PM EDT
[#26]
They are made in both 1x7 and 1x9 twists, although I went with the middle of the road 1x8, as it is said to effectively stabilize any bullet weight that will fit in AR magazines (50 grain up to 90 grain if I'm not mistaken).
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Posted: 10/7/2015 3:29:54 PM EDT
[#27]
I'm doing two right now and decided on 1/8 for me and my son. Just to get the broadest spread, we will dial them in and reload what works best.
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Posted: 10/7/2015 5:42:26 PM EDT
[#28]
Quote HistoryQuoted: They are made in both 1x7 and 1x9 twists, although I went with the middle of the road 1x8, as it is said to effectively stabilize any bullet weight that will fit in AR magazines (50 grain up to 90 grain if I'm not mistaken). According to my inputs in Berger's twist calculator, 75gr AMAX and 80.5/82gr Bergers have about a "marginal" 1.3 - 1.4 Sg, where 1.5 is considered properly stabilized and maximizes the B.C. (ETA: I think this is why Krieger uses 1:7.7) Guarantees the 75-77gr HPBT or TMK, which are considered the longest that are usable in mag length. |
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Posted: 10/7/2015 6:08:47 PM EDT
[#29]
Quote HistoryQuoted:
Bushmaster makes (or made) a 1/9 twist. I would stick with 1/7, more versatile Quote HistoryQuoted:
Quoted:
Are A2 20" profile barrels made in both twist rates? Thank you Bushmaster makes (or made) a 1/9 twist. I would stick with 1/7, more versatile They made both. My "A4" ish Bushmaster upper is a 1/7. |
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