Which twist 1:7 or 1:8? [Archive] - Glock Talk

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jdavionic
02-20-2010, 17:50
I am building another AR and have decided to go all out with trying to make it as accurate for longer distance shooting as I can get it (or at least as accurate as I can afford).

I've been looking at White Oak barrels.
http://www.whiteoakarmament.com/

They seem to be decent quality, although I'd certainly welcome opinions on them...or recommendations for better barrels.

But where I'm stumped is on deciding which twist - 1:7 or 1:8. I know these ratios are both good for shooting heavier rounds. My thought is that 1:7 will have slightly better results than 1:8 since it will offer just a little better stability for the bullets in flight.

Your thoughts? Barrel mfg opinions?

faawrenchbndr
02-20-2010, 17:58
1 in 7 is better for stabilizing hearier rounds. White Oak barrels are very good.

javelinadave
02-20-2010, 18:17
hearier
Is that Japanese for heavier?:supergrin:

jdavionic
02-20-2010, 18:21
1 in 7 is better for stabilizing hearier rounds. White Oak barrels are very good.

Thank you! I expect it will take some time before I get all of the pieces that I've picked out which so far are...

Geissele Match Rifle trigger

Magpul PRS stock

WOA Barrel & matching bolt...specifics TBD depending upon some more research. But I've heard good things about their barrels, including your feedback.

Upper - Not sure on the upper yet. I'm thinking of the Vltor or LaRue. This is somewhat depending on the barrel choice (e.g., M4 feedramps)

Lower - I went with RRA, since I have one. Hopefully it will be fine. I can't imagine that it will be an issue.

Handguard - LaRue Tactical 12.0

Scope - TBD. All I know at this point is that my taste far exceeds my wallet. However, I will not skimp on the glass. If I have to save for quite some time, then so be it.

faawrenchbndr
02-20-2010, 20:48
Is that Japanese for heavier?:supergrin:

Nope,.....just means my old *** can't type worth a pizz! :rofl:

faawrenchbndr
02-20-2010, 20:54
Thank you! I expect it will take some time before I get all of the pieces that I've picked out which so far are...

Geissele Match Rifle trigger
Outstanding choice!

Magpul PRS stock
Very nice stock for a precision weapon

WOA Barrel & matching bolt...specifics TBD depending upon some more research. But I've heard good things about their barrels, including your feedback.

Upper - Not sure on the upper yet. I'm thinking of the Vltor or LaRue. This is somewhat depending on the barrel choice (e.g., M4 feedramps)
Either would be fine, M4 cuts are not completely needed. Just remember, the barrel MUST have them if the receiver does.

Lower - I went with RRA, since I have one. Hopefully it will be fine. I can't imagine that it will be an issue.
RRA is good quality

Handguard - LaRue Tactical 12.0
Outstanding choice!

Scope - TBD. All I know at this point is that my taste far exceeds my wallet. However, I will not skimp on the glass. If I have to save for quite some time, then so be it.
The Leupold Mark IV is a great scope, as well as the Tactical Nikon models


:supergrin:

jdavionic
02-20-2010, 21:32
Thanks! For scopes, I've been mainly focused on the Leupold scopes. I've been reading about others like the Burris XTR, Valdada IOR, etc. But Leupold has an excellent reputation.

USMC03
02-21-2010, 07:01
1/7" vs 1/8" ...... Read the info I wrote in this post:

http://www.m4carbine.net/showthread.php?t=29302



1/8" twist is a more versatile twist and will shoot a wider range of bullets. About the heaviest bullet being used in an AR is an 80 grain, and due to the length the 80's won't fit in a magazine and have to be fed by hand. Both 1/7" and 1/8" will handle the 80's very well. As AR shooters, the heaviest round we commonly use are 77 grain bullets. Both Both 1/7" and 1/8" handle the 77's very well.

So both have the heavier bullets covered. Remember slower twist rates for lighter bullets and faster twist rates for heavier rounds. With the 1/8" being a little slower, it will handle some lighter rounds that the 1/7" may have problems with. Both the 1/7" and 1/8" shoot 55 - 77 grain bullets well.


In my opinion, the 1/8" twist is the best compromise in barrel twist between the 1/7, 1/8, and 1/9 for most civilian and law enforcement shooters when you consider the bullet weights most of us are shooting.

jdavionic
02-21-2010, 07:18
1/7" vs 1/8" ...... Read the info I wrote in this post:

http://www.m4carbine.net/showthread.php?t=29302



1/8" twist is a more versatile twist and will shoot a wider range of bullets. About the heaviest bullet being used in an AR is an 80 grain, and due to the length the 80's won't fit in a magazine and have to be fed by hand. Both 1/7" and 1/8" will handle the 80's very well. As AR shooters, the heaviest round we commonly use are 77 grain bullets. Both Both 1/7" and 1/8" handle the 77's very well.

So both have the heavier bullets covered. Remember slower twist rates for lighter bullets and faster twist rates for heavier rounds. With the 1/8" being a little slower, it will handle some lighter rounds that the 1/7" may have problems with. Both the 1/7" and 1/8" shoot 55 - 77 grain bullets well.


In my opinion, the 1/8" twist is the best compromise in barrel twist between the 1/7, 1/8, and 1/9 for most civilian and law enforcement shooters when you consider the bullet weights most of us are shooting.

Thanks! I've never ventured into that site. I read your post and it was very informative. The pics on the match were interesting as well.

Mike5560
02-21-2010, 08:23
I agree with USMC. I recently was researching the trade-offs between the two. For the longest time most AR manufacturers have been making mostly 1:7 or 1:9 twists. But recently on some newer models I've been seeing 1:8 spring up. I had to see the reason behind this.
The heaviest most AR shooters will use is 77 grain. 1:7 and 1:8 twists will both stabilize these, but 1:8 will allow you more flexibility for some lighter varmint bullets.