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Discussion Starter · #1 ·
I am looking at getting an AR or the Sig 556. The sigs twist is 1/7, and I have read that most ARs ar 1/8, 1/10, 1/14, it looks to me that 1/8 is the prefered twist. so why would sig do 1/7? i know it takes in acount bullet wieght and then the distances you plan on shooting, should I shy away from a 1/7 twist like the sig? or will it matter. I wont be shooting it alot, I do want to reach out to 200 plus..

please give me your thinkings on this????????
 
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Discussion Starter · #2 ·
I like 1/9 twists. The lower the twist the better for heavier grain bullets. A dedicated .22 upper is like a 1/12.
 
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Discussion Starter · #3 ·
1/7 is what the military uses for the twist on barrels. All of our issue rifles are 1/7.

My AR is a 1/9 which will stablize most of the bullets out there not all of them. The 1/7 will stablize pretty much all the bullets for .223/5.56 out there.

You're good to go with a 1/7

Check out www.ammo-oracle.com for the real scoop on twist rates.
 
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Discussion Starter · #4 ·
I am liking everything i read about the SIG 556, with the gas piston, and the 1/7 twist. Also i have read that the 1/7 will wear the barrel out faster then others but I'm not going to shoot thousands of rounds, I know there are AR's coming out with the gas piston, and the chromed lined chambers. Any one have a AR favorite? with these newer mods?
 
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Discussion Starter · #5 ·
I am liking everything i read about the SIG 556, with the gas piston, and the 1/7 twist. Also i have read that the 1/7 will wear the barrel out faster then others but I'm not going to shoot thousands of rounds, I know there are AR's coming out with the gas piston, and the chromed lined chambers. Any one have a AR favorite? with these newer mods?
The 1in7 twist is too fast for distance shooting with the most common .223 rounds out there 55-62 grainers and will lead to premature barrel replacement. The Govt uses that twist to stabilize the tracer which is longer than the standard round. Truthfully 1in9" is the best compromise for barrel life and compatibility with available ammo. The main reason the 1in7" twist has taken hold is due to the internet commando's having to have everything to mil spec.
 
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Discussion Starter · #8 ·
I have a Savage with a 1-7 twist, so I can shoot 80 and 90 grain Berger VLDs. Unless you're shooting heavy bullets, 1-9 works fine.
 
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Discussion Starter · #9 ·
Who cares what the twist is, get the 556!!! I have not had the chance to shoot one but I got to hold one and they are very well balanced and just feel right. One of my brothers got to shoot a LE sample and loved it and he has fired almost every SMG in the FBI's arsenal. You won't go wrong with the Sig 556.
 
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Discussion Starter · #11 ·
I am looking at getting an AR or the Sig 556. The sigs twist is 1/7, and I have read that most ARs ar 1/8, 1/10, 1/14, it looks to me that 1/8 is the prefered twist. so why would sig do 1/7? i know it takes in acount bullet wieght and then the distances you plan on shooting, should I shy away from a 1/7 twist like the sig? or will it matter. I wont be shooting it alot, I do want to reach out to 200 plus..

please give me your thinkings on this????????
You dont need 1/7 to reach out to 200 yards.
You do need 1/7 to shoot the m856 tracer round, or 75 grain and up.

LMT, Colt, Sabre and some resellers for Bushmaster and RRA sell 1/7 twist for AR's. Its pretty much becoming the standard... thats why the sig has it.
 
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Discussion Starter · #12 ·
You'll be hard-pressed to find commercial 5.56mm/.223cal over 62gr at your local sporting goods store. Keep this in mind and go 1/9! ;)

If you handload or have a good supplier of heavy stuff, I'd go 1/7 for 600yd fun!
 
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Discussion Starter · #13 ·
The 1-in-9 twist is supposed to be good up to 69-grain bullets, so you've got a good selection of bullets to use with that twist rate, with a "sweet spot" of 60 to 62 grains. My AR has a 1-in-9 twist and so far the heaviest bullet I've used is a 62-grain FMJ from Prvi Partizan. That company puts out a decent cartridge. Just remember that it will behave differently than the SS109 62-grain bullet with a steel penetrator and you'll do fine.
 
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Discussion Starter · #14 ·
You'll be hard-pressed to find commercial 5.56mm/.223cal over 62gr at your local sporting goods store. Keep this in mind and go 1/9! ;)

If you handload or have a good supplier of heavy stuff, I'd go 1/7 for 600yd fun!
Unless you're doing match shooting for extreme accuracy, standard 55gr. works just fine in a 1/7 barrel according to what I've read. 62 is preferred, but 55 is the minimum weight that is still stable.
 
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Discussion Starter · #15 ·
I use 1-7 on my 1,000 yard upper. Yes, the .223 WILL shoot 1,000 yards, and there is mort to this barrel than just the twist.

Most NRA cross-the-course rifles are 1-8, a few use 1-9; but they lose out at 600 yards. For most applications the 1-8 or 1-9 are fine.

I know some of the IPSC type shooters who shoot short distance (under 300 yards) use 1-10 or even a 1-12 because they are shooting 55 grainers at over 3k FPS.

The beauty of the AR is the flexibilty in the weapons system. You can change the upper and have a new weapons system.

Good luck and enjoy.
 
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