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.243 vs .260 in a large frame AR

m1ajunkie

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Minuteman
Feb 22, 2010
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Boise, ID
I am looking for a new caliber to add to my lmt mws. Rifle is used for plinking, but its my go to rifle for matches. I normally shoot steel out to about 1200yds max, and never hunt with it.

I have been set on .260 for some time, but the more I read the more I feel its limited by the 20" barrel. How does .243 fair out of autoloaders with 20" barrels? Would I be better off on drop and drift with the .243? How about reliability?

I guess I would just like to know if there is any reason I should avoid either of these calibers in a 20" gas gun? Fwiw, the rifle will be shot almost full time with a surefire 762ss suppressor.
 
Re: .243 vs .260 in a large frame AR

I'd suggest 6 or 6.5 Creedmoor for a gas gun running a 20" barrel. You'll get same peformance as the extra case capacity of 243 or 260 will be reduced by the magazine OAL constraint causing bullet to be buried in case.

Additionally, you'll have a bit less gas volume to deal with running the gun suppressed with Creedmoor vs. 308 sized case.

YMMV
 
Re: .243 vs .260 in a large frame AR

6mm creedmore would be my favorite choice but I haven't been able to get a barrel from gap without providing the mws barrel parts which I haven't been able to acquire.

I haven't looked much into 6.5 creedmore due to the fact I only know of hornady as a brass supplier. Although I'm certainly open to that if the brass supply isn't an issue.

I keep hearing that lmt is going to release 5r versions of these alternate calibers, but so far I haven't seen them. I guess I've got time to decide while I wait on the release.
 
Re: .243 vs .260 in a large frame AR

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DavidAR10</div><div class="ubbcode-body">Have you talked to our local folks at AO?

I also thought of the 6mmCM but the barrel life...
have two kids in college.
</div></div>

I have not, I actually didn't think about giving them a call. I was just planning on picking up one of the factory lmt barrels, but going custom may be a better idea because I could possibly get a longer barrel in whatever caliber I go with.