1/7 twist - AR15.COM

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Posted: 3/15/2005 11:11:30 AM EDT

I cant decide whether to get a Bushmaster 14.5 inch barrel with a 1/7 twist ot 1/9 twist. Ive heard that 1/7 twist wears down faster...is that true?

Help me decide. What are the pros and cons of the 1/7 and 1/9?

Posted: 3/15/2005 11:18:14 AM EDT

[#1]

Faster? Yes.

Will the rifling wear out before the throat? Highly unlikely.

So the point is moot.

If you plan on shooting heavy ammo, get the 1/7 (will also handle many lightweight bullets just fine).

If you're fine shooting mainly 55-69gr ammo, the 1/9 is for you.

Posted: 3/15/2005 11:18:38 AM EDT

[#2]

I can't believe that a person who's been here over a year and had over a thousand posts doesn't know the answer to such a basic question and doesn't even know to put it in the correct forum.

Posted: 3/15/2005 11:18:48 AM EDT

[#3]

what ammo are u going to shoot?

junk surplus?

if so thats 55 to 62gr.
stick with 1/9

1/7 is for 80g match ammo

Posted: 3/15/2005 11:22:10 AM EDT

[#4]

Depends upon what bullets you want to shoot. If you want to shoot the heavier 77g bullets, or military tracers, or shoot in extremely cold weather, go with 1/7. The military specs 1/7 because they shoot the longer tracer bullets which is longer than the standard FMJ 55g & 62g and needs the faster twist rate to stabilize. Some say that the 1/7 will also cause more barrel wear, I can't confirm that personally. Otherwise 1/9 is sufficient. The NRA(?) ran some tests a few years back, and they arrive at the 1/9 as being optimal.

Posted: 3/15/2005 11:24:20 AM EDT

[#5]

Ill mostly use it for plinking ammo such as 55gr and 62gr.....but I also want to be able to use it for self defense type heavier rounds, and tracer rounds on occasion.

Posted: 3/15/2005 11:27:05 AM EDT

[#6]

Quoted:
Ill mostly use it for plinking ammo such as 55gr and 62gr.....but I also want to be able to use it for self defense type heavier rounds. And tracer rounds on occasion.

Then get the 1/7.

Posted: 3/15/2005 11:27:31 AM EDT

[#7]

Quoted:
Ill mostly use it for plinking ammo such as 55gr and 62gr.....but I also want to be able to use it for self defense type heavier rounds. And tracer rounds on occasion.

Get a variable twist barrel then!

Posted: 3/15/2005 11:28:34 AM EDT

[#8]

Get a variable twist barrel then!

What....never heard of it.....sounds expensive.

Posted: 3/15/2005 11:31:20 AM EDT

[#9]

Quoted:
Ill mostly use it for plinking ammo such as 55gr and 62gr.....but I also want to be able to use it for self defense type heavier rounds. And tracer rounds on occasion.

Self defense? If you ever have to use it for that purpose, you will be prison faster than the perp. Juries look down on using assualt weapons for self-defense.

I would run this by some at Bushmaster and see what they say. They would know their products the best.

Posted: 3/15/2005 11:34:18 AM EDT

[#10]

Quoted:
Quoted:
Ill mostly use it for plinking ammo such as 55gr and 62gr.....but I also want to be able to use it for self defense type heavier rounds. And tracer rounds on occasion.

Self defense? If you ever have to use it for that purpose, you will be prison faster than the perp. Juries look down on using assualt weapons for self-defense.

I would run this by some at Bushmaster and see what they say. They would know their products the best.

Nobody has ever been convicted in a LEGAL SD situation based on how evil a weapon looks.

Posted: 3/15/2005 11:38:55 AM EDT

[#11]

Quoted:

Nobody has ever been convicted in a LEGAL SD situation based on how evil a weapon looks.

Brou,
He's in CA - it might be possible there.

Posted: 3/15/2005 11:41:10 AM EDT

[#12]

brouhaha: Yeah, I know but you want to stack the odds in your favor. Most ordinary people don't know the diff between a broomstick and a buttstock. You can bet that during a trial, anybody that knows about firearms will be dismissed, and all you get are the soccer-mom types that don't know the difference between their @$$ and a hole in the ground.

Personally, I would get the 1/9 twist.

Posted: 3/15/2005 11:46:22 AM EDT

[#13]

Get the 1/7, options, options, options...

BTW, you won't miss anything from lightweight, 40gr or less, ammo that you can't shoot. There's plenty of heavier ammo that can do what they can do but none of the light weight ammo can do what the heavy stuff can...

Posted: 3/15/2005 11:48:14 AM EDT

[#14]

Quoted:
Quoted:
Ill mostly use it for plinking ammo such as 55gr and 62gr.....but I also want to be able to use it for self defense type heavier rounds. And tracer rounds on occasion.

Self defense? If you ever have to use it for that purpose, you will be prison faster than the perp. Juries look down on using assualt weapons for self-defense.

I would run this by some at Bushmaster and see what they say. They would know their products the best.

I would hope that if I ever have to fire my AR at a perp, he would be immediately incapacitated and hopefully die soon thereafter, not go to prison. As far as a jury is concerned, I will worry about that after the event is over and I am still alive and able to give a damn. After all, I am not a cop, and if I have to use my AR the SHTF and my survival is not guaranteed anyway. Which brings us back to the logic of using the best weapon for the job, juries be damned.

Posted: 3/15/2005 11:48:35 AM EDT

[#15]

Quoted:
brouhaha: Yeah, I know but you want to stack the odds in your favor. Most ordinary people don't know the diff between a broomstick and a buttstock. You can bet that during a trial, anybody that knows about firearms will be dismissed, and all you get are the soccer-mom types that don't know the difference between their @$$ and a hole in the ground.

Personally, I would get the 1/9 twist.

Just differing opinions. I would prefer to use what I am most proficient with. For me, that's an AR. If that's not around, I'll use whatever I have handy. Even if it's a pair of flip-flops to slap them silly.

The whole carried by 6 - judged by 12 thing comes into play.

But Forest has a point. Political climes are much different in your location than in mine.

To each their own

Posted: 3/15/2005 12:10:27 PM EDT

[#16]

1/7

Posted: 3/15/2005 12:22:51 PM EDT

[#17]

So is it out of the question to fire high velocity 40gr. rounds out of a 1/7?

Posted: 3/15/2005 12:35:47 PM EDT

[#18]

Quoted:
So is it out of the question to fire high velocity 40gr. rounds out of a 1/7?

Not out of the question - but some brands might not make it to the target.

Posted: 3/15/2005 4:12:35 PM EDT

[#19]

I have a 1 in 7 colt match target and a 1 in 9 savage 110. The savage shoots 1/2 groups with 69 grain bullets. Not so good with 75 or 77. The colt shoots the 77s ok and 63 grain mil surp ok. The savage is by far the best shooter. Use the ar 15 solution, buy both.

Posted: 3/15/2005 4:14:15 PM EDT

[#20]

Quoted:
Quoted:
Ill mostly use it for plinking ammo such as 55gr and 62gr.....but I also want to be able to use it for self defense type heavier rounds. And tracer rounds on occasion.

Get a variable twist barrel then!

Posted: 3/15/2005 4:24:32 PM EDT

[#21]

heavy ammo: 1-7
lighter ammo (45gr-69gr or so) : 1-9

Posted: 3/15/2005 5:58:09 PM EDT

[#22]

Quoted:
heavy ammo: 1-7
lighter ammo (45gr-69gr or so) : 1-9

Not totally true.

I've shot plenty of handloaded 40gr Vmax thru a 18" 1/7.

There's only a select few bullets that can't handle the stress and fly apart.

Posted: 3/15/2005 6:00:13 PM EDT

[#23]

Get a 1/12 twist barrel.

Posted: 3/15/2005 6:46:05 PM EDT

[#24]

As many have stated in this thread it all comes down to preference. Most of you MIL-Over run is 55gr.-62 gr. If you plan on shooting ALOT, want to keep costs down by buying cheaper ammo then go with the 1/9. If you plan on doing competition shooting still go with the 1/9. You can shoot almost ANYTHING out of a 1/9 and get good results. Now if you are planning on shooting over 300 yrds then maybe you'd want the 1/7 and shoot some 75's or 77's. Seems to me the 1/9 is the MOST versatile and therefore the best choice.IMHO.

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