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Posted: 6/17/2001 10:24:02 AM EDT
I am in the process of trading for a 1 in 7 HBAR and I had no idea that this might be a problem until I talked with another shooter at the range today. He claims that 1 in 7 causes all kinds of premature barrel wear while using 55 grain bullets. Any truth to this? I don't really want the barrel if I cannot use 55 grain in it without damaging it. After all, I have copious amounts of 55 grain and no heavier grain bullets in my inventory.
Link Posted: 6/17/2001 10:28:57 AM EDT
[Last Edit: 6/17/2001 10:34:36 AM EDT by raf]
Link Posted: 6/17/2001 11:35:59 AM EDT
Not my own experieence but I had a fella at the local gun shop tell me when he was in the army they tried shooting 55s thru a 1 in 7 at 100 yds and were getting 20 inch groups
Link Posted: 6/17/2001 12:13:25 PM EDT
Get blackhills 75gr match ammo. You will like the results. Blue box about $13 to $18 for 50.
Link Posted: 6/17/2001 12:17:53 PM EDT
Fast (1/7, 1/8) twists will stabilize light & heavy bullets. Slow (1/10, 1/12) twists will only stabilize light bullets.
Link Posted: 6/17/2001 12:36:47 PM EDT
Link Posted: 6/17/2001 3:00:10 PM EDT
In the Army's manual FM 23-9 pages F-14 to F-16 addresses the issue of using 55gr M193 compared to 62gr. M855. The manual says that out to 500 meters there is little difference in accuracy between the two rounds with the M16A2 with the 1:7 barrel twist. The only thing that matters is if you are using 55gr. zero the rifle with 55gr. or if you use 62gr zero with 62 gr. I think that out to 300 meters there is very little diffence if you for example zeroed with 55gr and were shooting a 62 gr. Beyond 300 meters you would have to compensate by using more or less elevation. I have read that with the 1:7 twist you cannot shoot 55gr soft points or hollow points because the twist is so fast that the bullets disenegrate not to long after leaving the barrel. 55gr FMJ should work fine or if you want to shoot hollowpoints or soft points use a 60gr or higher. On Bushmasters web site they say that they switched from a 1:7 to a 1:9 twist because the militarys barrels were wearing out prematurely but this was using full-auto so I would not think that it would be a concern. Both of my AR's have the 1:9 twist which is probabbly the most versatile. You could always switch out the barrel and keep the 1:7 as a spare.
Link Posted: 6/17/2001 3:10:42 PM EDT
The answer is yes, it is perfectly A.O.K. A fast twist can shoot light bullets but a slow twist cant shoot heavy ones. You probably will never burn out that barrel in your lifetime unless you want to prove a point and burn it out GG
Link Posted: 6/17/2001 4:20:30 PM EDT
Thanks for the info guys. I feel alot better about the trade now.
Link Posted: 6/17/2001 4:47:42 PM EDT
You probably will never burn out that barrel in your lifetime unless you want to prove a point and burn it out
View Quote
Guess I had a few points to prove. Was that remark directed at AR barrels only? I've never shot out an AR barrel, but I've sent three others to an early grave. Eddie
Link Posted: 6/17/2001 5:15:27 PM EDT
I posted the same question not to long ago and got all positive answers. Some guys said that they even shoot 55 gr in a 1/7 in matches. Personally, I've shot one inch groups at a hundred yards with iron sights. Accurate enough for me. If the only thing your worried about with the trade is the twist, I say go for it.
Link Posted: 6/17/2001 6:33:50 PM EDT
I shoot them (55 grain) all the time in my 1/7 HBAR colt. They may not be the most accurate, but I get 2.5" groups at 100 yds and I'm not what you would call a skilled marksman. Reverend73
Link Posted: 6/18/2001 2:35:37 PM EDT
Link Posted: 6/18/2001 3:22:31 PM EDT
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