Which 7mm round for AR build??

[Blasst]

After reading this article about a 7mm WSM (bolt gun) shooting half-MOA at 1000 yards off a bipod I have always wanted to build (or have someone build) an AR in 7mm....and see what kind of groups I could squeeze out of a gas gun.

http://www.6mmbr.com/gunweek064.html

The shoulder on the 7 wsm cartridge is too steep for reliable feeding according to GAP and I believe them. Other gunsmiths do them but I am skeptical .....nothing is worse than an AR that won't feed reliably. 7-08 is done a lot so it is a possibility but I wish it held a little more powder. If I remember right the 7 saum cartridge production has been dropped.

I will do handloading for ultimate accuracy but want to stay with a cartridge that is also commercialy available and will work in an AR......so it looks like 7mm-08
is about the only choice in 7mm.............am I missing anything. Any other 7mm rounds people have had success with in an AR??

Thanks, Jim

 

[juliomorris]

Re: Which 7mm round for AR build??

The 7mm-08 is an excellent round and a very accurate round. You could get a little more velocity if you went with an AI but I'm not sure how it would feed. one of the biggest things the 7mm08 or 7mm08 is components for reloading. You can neck down any 308 brass, and there is a pretty good selection of bullets. I have gotten excellent accuracy out of Hornady 139 sst's and the 162 gr Amax. I recently started working up loads using Berger 140 and 168s with goodresults. You should be able to fined alot of reload info or the net. I have been able to push the 139s at 2950fps out of a 22" barrel now that is not anywhere near what you can get with the short mags. You should get about another 100fps with the AI. You might want to look at the 243 or 260 also both are very good long range rounds. Check this site for info on 6mm and 7mm: http://www.6mmbr.com/6mmbr.html Sorry didn't notice you already have that site.

 

[Blasst]

Re: Which 7mm round for AR build??

yes...I agree on the 260 and other 6mm and 6.5's. I was going with the 7mm as a compromise. Better wind bucking than the smaller rounds, high BC bullets available, and flatter shooting than the 308. So yeah I agree...the 7-08 is a good round and really the only one I have come up with that I can also get off the shelf if I run out of hand loads.

thanks,
jim

 

[bohem]

Re: Which 7mm round for AR build??

7 SAUM isn't dropped, Remington still makes model 7's in it. Brass is available through Remington, I wish Win would make it because the quality of their brass seems to be a little better from my experiences with it.

I have a 7 SAUM that I like quite a bit and I've found it to be very accurate and very easy to load for.

I think DPMS makes a 300 SAUM upper, using that and putting a 7mm tube on it would get you that long action 7mm performance (SAUM is like a hot 280 Rem)