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View Full Version : 1:7 or 1:9 AR Barrel Twist ?


mc209
02-08-2010, 12:19 AM
Looking for an 16inch upper assembly. Interested in the Daniel Defense uppers but concerned with 1:7 twist affecting the accuracy of the low grain bullets of .223 and 5.56 round. Wouldnt mind going with a heavier grain but hard to come by at your local wally, big 5 and even bass pro! Would it be best to stick with the bigger variety of 1:9 uppers since it handles that grain better? Will be used for target and a SHTF build. Any advice would be welcomed. Thanks.

AlliedArmory
02-08-2010, 12:23 AM
1:7 and 1:9 will both handle 55gr with no issues. 55gr is the most widely common gr for 223/5.56

Jeffu
02-08-2010, 12:30 AM
I'm pretty sure 55grain is best with 1:9 right?

CCTACTICAL
02-08-2010, 12:40 AM
I'm pretty sure 55grain is best with 1:9 right?

Yes. 1:7 with your 62 grain and up. 1:7 Way to fast a twist rate with 55g.
But that just me.

battleship
02-08-2010, 12:59 AM
I shoot 55 grain out of a sig 556 which has a 1:7 twist, only because its cheap and available everywhere. Picking up a Ruger SR 556 next week with the 1:9 barrel, it will be interesting to see the difference in groups at the 50 yard line.
Whats better, well it really depends on your application for the rifle and your wallet.
1:9 twist can handle 55 grain up to the low 70's so i think its an all rounder.

aplinker
02-08-2010, 2:10 AM
I shoot 55 grain out of a sig 556 which has a 1:7 twist, only because its cheap and available everywhere. Picking up a Ruger SR 556 next week with the 1:9 barrel, it will be interesting to see the difference in groups at the 50 yard line.
Whats better, well it really depends on your application for the rifle and your wallet.
1:9 twist can handle 55 grain up to the low 70's so i think its an all rounder.

At 50yds, the differences in grouping will be due to you & your ammo, not the rifle.

A good AR should is easily capable of 1-2MOA, at minimum.

If you will only ever shoot 55gr, then 1:9 is a better choice. There's absolutely nothing wrong with shooting even light varmint (45-50gr) rounds from 1/7, but it is really optimized for when you'd like to shoot the longer (heavier) rounds.

k1dude
02-08-2010, 2:15 AM
I shoot 55 grain out of a sig 556 which has a 1:7 twist, only because its cheap and available everywhere. Picking up a Ruger SR 556 next week with the 1:9 barrel, it will be interesting to see the difference in groups at the 50 yard line.
Whats better, well it really depends on your application for the rifle and your wallet.
1:9 twist can handle 55 grain up to the low 70's so i think its an all rounder.

Keep in mind that during testing, Ruger found the best factory load accuracy out of the SR556 with their 1:9 barrel occured when using 77 grain bullets.

Jonathan Doe
02-08-2010, 7:09 AM
I had a 1-8" twist Wilson barrel that shot Federal and Remington 55 grain SP bullet with a very good accuracy.

Evo
02-08-2010, 11:22 AM
If I wanted to use a 22LR conversion which would be the better twist choice?

BigBamBoo
02-08-2010, 12:04 PM
............

mif_slim
02-08-2010, 12:06 PM
^ Nice shooting! Nice AR too. How's that comp working out for you?

Hornet_RN
02-08-2010, 12:18 PM
get a 1:9 twist barrel if all you are shooting is 55 grain ammunition. i would ESPECIALLY buy a 1:9 twist barrel if all you are doing is target shooting, and even 3-gun shooting.

i would only get a 1:7 twist barrel if you are only going to use heavier grain ammunition like 69 grain and up and are shooting for accuracy. Theoretically, the faster twisting of the bullet due to a 1:7 twist should keep the heavier bullet stable while in air...or so i have read...heh.

Bug Splat
02-08-2010, 12:39 PM
Twist to gr is more of a guideline not fact. You will never know what your barrel likes until you try it. Some barrels like light rounds and some like heavy. I had a very odd barrel that only liked heavy 69gr bullets or 40gr bullets. Hated everything in between.

AM9000
02-08-2010, 5:34 PM
All my AR's are 1/7 and most have never seen anything but 55gr. I have been more than satisfied with the accuracy with all of them.

I can hit the 400 yard gong at Angeles with 9/10 shots when I slow it down and focus. That being said, I am not a paper killer. Most of my groups are measured with eye balls.

pyro3k2
02-08-2010, 6:11 PM
just get a 1:8 twist and shoot the hell out of it

xaaronx
02-08-2010, 8:46 PM
1/7 handles 55g just fine.

sreiter
02-08-2010, 9:15 PM
55gr winchester 5.56 out of my BCM 1:7 twist using a red dot only @ 50yds (with my failing/aging eyes)..red circle is 4 inches in diameter

http://photos-b.ak.fbcdn.net/hphotos-ak-snc3/hs158.snc3/18576_1361284596448_1361558845_1031607_2965544_n.j pg

Bongos
02-08-2010, 10:02 PM
1:9 up to 69gr
1:7 higher than 69gr
1:16 for 22 LR (1:9 if you are using a conversion kit)

Acorn556
02-08-2010, 10:21 PM
I wouldn't worry about it unless you're going to do competition. I have a 1:9 barrel and it's taken everything just like the rest. I would say it's more MY SHOOTING thats not hitting sub MOA groups than the ammo. I typically use WWB though.

mc209
02-09-2010, 12:40 AM
Thanks for the replies, if you can post your findings here battleship that will be great. A 1:8 twist seems like the best of both worlds but don't see many manufacturers doing that twist. Deciding between DDXV 1:7 and a Delton or Stag 1:9 due to reviews, price and feedback from folks. Any first hand input on those or any others would be great. Thanks!

aplinker
02-09-2010, 1:38 AM
That's not even a question. The $550 DD XV upper is simply the best choice, by far.

DDRH
02-09-2010, 7:38 AM
i think addax has a gpu with 1/8 chromelined 16" barrel...