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View Full Version : Is 1:7 Twist the Way To Go?


insin
12-14-2006, 9:25 AM
I currently have rifles that have the 1:9 twist ratio but am looking into possible future builds. I for some reason think that I should go with 1:7. I know that the heavier gr. bullets may perform better from these 1:7 barrels, but will I be limiting myself to shooting only 62+ gr rounds? Most of what I have shot/bought thus far have been this weight (62gr), but there are so many good types of 55gr bullets out there. There are also the rounds that are heavier then 62gr that I wouldnt mind being able to get into.

So is going 1:7 on all my barrels the wrong thing to do, if hypothetically I went that route? Im just looking for opinions since I know there isnt really a right or wrong answer.

mltrading
12-14-2006, 9:27 AM
The 55gr ammo shoot good with 1/7 BBL.

radioactivelego
12-14-2006, 9:31 AM
Can't go wrong with a 1:7. From what I've read in books you only run into problems with overtwist in very large, heavy bullets (we're talking 250+).

bear93445
12-14-2006, 9:36 AM
check out the AR15 forum, lots of info

http://www.ar15.com/forums/

Jack_Bauer
12-14-2006, 10:04 AM
Check out http://www.ammo-oracle.com/ too

tenpercentfirearms
12-14-2006, 10:13 AM
Wait, there is a very logical way to look at this. You already have 1:9 twist rate, keep those. Then your next upper should be 1:7. There is no reason not to have several different types of uppers in all sorts of configurations.

Black rifle disease, catch it!

DedEye
12-14-2006, 3:16 PM
For my first OLL I decided to go with a 1:7 twist. I don't have any experience with 1:7 and 1:9 BBLs myself, but was told that I'd get more versatility out of the 1:7.

Now on a related note, I've been looking for a 1:7 complete upper. LMT looks like a good choice, but what would you all suggest?

rksimple
12-14-2006, 4:17 PM
LMT is good stuff. If you ever plan on shooting 68 gr and up ammo, like TAP, mk262, etc, the 1 in 7 is the best way to go. My Stag 1/9 16 in carbine will not stabilize 68 gr Hornady HPBT's. YMMV.

tenpercentfirearms
12-14-2006, 7:08 PM
You won't go wrong with LMT and CMMG would probably be just as good, but lets consider them second.

1hotshooter
12-14-2006, 8:44 PM
Wait, there is a very logical way to look at this. You already have 1:9 twist rate, keep those. Then your next upper should be 1:7. There is no reason not to have several different types of uppers in all sorts of configurations.

Black rifle disease, catch it!

I double this sentiment

:)

petey
12-15-2006, 6:59 AM
When choosing a twist rate, you should consider the type of ammo you will be using. 55gr. and 62gr. milsurp ammo shoots fine in a 1:7 twist. You can also use 69gr. or other heavier rounds. However, if you want to shoot some lighter 40gr. or 45 gr. rounds, you might find that you have a .223 shotgun.

PIRATE14
12-15-2006, 7:39 AM
LMT is good stuff. If you ever plan on shooting 68 gr and up ammo, like TAP, mk262, etc, the 1 in 7 is the best way to go. My Stag 1/9 16 in carbine will not stabilize 68 gr Hornady HPBT's. YMMV.

It should be able to stabilize these rounds, have you tried any other manufactures in this range?.....

PIRATE14
12-15-2006, 7:49 AM
OKAY....you gotta ask yourself will you ever shoot anything heavier than 62gr ammo?

99 percent of you probably won't, that's why 99 percent of AR barrels are 1/9 twist.

Now MK262 is unobtainable for most as well as tracers so....

Hornady TAP PD is slower than TAP plus not many of you spring for ammo that is almost a buck around...

If you plan on using 77 BH, 75 TAP, MK262, Tracers, or heavier go w/ a 1/7.....

And as a general rule of thumb....get the hotest ammo you can find.

99 percent of my ARs are 1/7 but I am a high end type of guy and have lots of MK262 and tracers:D

joebob
12-15-2006, 7:56 AM
If you want to throw 80 grain match bullets, you need 1:7
80 grain bullets help mitigate wind effects at medium ranges, such as 600 yards.

DedEye
12-17-2006, 9:17 PM
I figured I'd be sticking with Milsurp, 55 and 62gr ammo for the most part. For paper shredding should I choose a different ammo / grain? I thought that the surplus ammo would be cheaper than most of the retail ammo I could get so it would make sense to get 1/7 for that reason.