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aslowdodge
06-22-2010, 1:21 PM
I'm looking at getting a 16 in mid and there are 3 twist rates. 1:7 seems most common ( like 90%), but 1:8 looks lie a good compromise between 1:7 and 1;9 to shoot all weights with a little less wear factor.
Any thoughts on this?

Peter W Bush
06-22-2010, 1:23 PM
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ar15barrels
06-22-2010, 2:55 PM
Slower twist rates will result in smaller groups IF crappy bullets are being used.
Faster twists will allow the use of heavier/longer bullets to be used.

Be honest with yourself.
If you are only going to be using 55gr up to 69gr bullets, get the 1:9 twist.
If you really ARE going to run 75's and 77's, then get the 1:8 twist.

AlliedArmory
06-22-2010, 3:21 PM
I have used 1:9 and 1:7. I shoot only 55gr and 62gr and have not seen any accuracy difference in either.

Only difference I saw in a group is when I shot some 75gr in my 1:7, but the group did shrink in half.

Since I shoot XM193 most of the time, the twist rate makes no difference to me. Especially since it's not a precision AR.

aslowdodge
06-22-2010, 4:37 PM
USE THE SEARCH BUTTON

Hey Peter, I did. A lot of posts that weren't that useful like those about heart rate monitors came up. That's why I asked. Thanks for your help anyways.

thayne
06-22-2010, 5:00 PM
Unless you plan on shooting light weight varmint bullets I'd say go with the 1:7 twist. It give you more versatility as far as using heavy long bullets

Peter W Bush
06-22-2010, 5:47 PM
Hey Peter, I did. A lot of posts that weren't that useful like those about heart rate monitors came up. That's why I asked. Thanks for your help anyways.

You are right. Sorry I wasn't being helpful.

bjl333
06-22-2010, 5:53 PM
The cheapest ammo I've seen in gunshows are 55gr. At that weight I don't think there are too much diffenence, but 1/9 would be the most common on the market.

Josh3239
06-22-2010, 8:47 PM
Your overthinking it if you aren't building a benchrest rifle, if you aren't building a benchrest rifle you won't see a difference in twist alone.

advocatusdiaboli
06-22-2010, 9:23 PM
I went with 1:7 which loses a bit in accuracy with the cheapest common bullets, but one day (I hope) the heavier rounds (in the 60-70 range) will be once again cheap and I'll be glad I sacrificed a bit of accuracy with the lighter. Well, that and the Spike's M4 ST-LE was a good deal and it was 1:7 twist stock ;-)

Lead-Thrower
06-22-2010, 9:51 PM
If you plan on using 55 grain FMJ's, I would get the 1:9. 55's suck out of 1:8 and 1:7 according to my experiences...

Rem1492
06-22-2010, 10:10 PM
I buy 1:9 because I use 55gr only, yeah its cheap and always pentiful.

Hardcore reloaders and what not, use heavier bullets and go for 1:7 twists.

1:9 is a do all twist rate.

Hoop
06-22-2010, 10:23 PM
if given the choice between 1:7, 1:8 and 1:9 I would take 1:8.

Hoop
06-22-2010, 10:25 PM
If you plan on using 55 grain FMJ's, I would get the 1:9. 55's suck out of 1:8 and 1:7 according to my experiences...

It depends on the shape of the bullet, I've shot tons of 52 grain match bullets out of my 1:8 as well as 55 FMJ red box black hills and both were more than accurate enough.

aslowdodge
06-22-2010, 10:38 PM
I guess in the end it really matters what bullets you'll be using. I guess 1:7 allows you to shoot the heavier stuff if SHTF, but practice with cheaper lighter ammo, but sacraficing a bit of accuracy in doing so. I guess we all want the optimal setup -money doesn't matter if our lives depended on it, but for what we use them for most of the time we'd like to save money.

My thought is to go with a 1:8 as the best compromise or 1:7 as this might be okay with cheaper ammo if the use is relatively cu ( like 200 yds or less) in a firefight as accuracy may not be as much of an issue.
I also want to build either a 308 or 6.5 grendal with maybe a 20 inch barrel for longer range sniping or hunting. Does this approach make sense?

aslowdodge
06-22-2010, 10:42 PM
You are right. Sorry I wasn't being helpful.

It's cool. I know dumb questions like mine that show up frequently can be a bit frustrating for people so I try not to ask questions without doing a search here or on google. Imagine my surprise when 10+ pages of finds, most which didn't answer the question came up on this forum ( although I know more about heart rate monitors now lol)

randy
06-23-2010, 2:40 AM
The current trend in 3 gun rifles is a 1:8 twist. At least that's what JP and MSTN are using. Many people use a 69 grain bullet. I've tried 50,55,68,69,75,77. I gotta say out of my 18" JP 1:9 (before the current treand) the 55's work great and I'm happy with the performance at 350 yards.

Peter W Bush
06-23-2010, 2:53 AM
It's cool. I know dumb questions like mine that show up frequently can be a bit frustrating for people so I try not to ask questions without doing a search here or on google. Imagine my surprise when 10+ pages of finds, most which didn't answer the question came up on this forum ( although I know more about heart rate monitors now lol)

There is an excellent article out there somewhere about twist rates. I'll post it when I find it. Basically, 1/8 is great considering you can fire 55gr-77gr accurately out of it. Try not to stress about it too much... This probably wont be your only AR :43:

aslowdodge
06-23-2010, 11:33 AM
lol- it is my 2nd ar. The first was built with a spikes dedicated 22 upper that I haven't even shot yet. I am already planning a 3rd in either the 308 or 6.5 grendal- but I will wait before I start asking stupid newbie questions on that one. The disease is bad here. I just got into guns in April!