XCR and SL8

[aninchlow]

I've got a bunch of IMR 4320 and I'm about to buy a few boxes of bullets. I've got a SL8 and a XCR that eat 5.56 like it's going out of style. I want to switch to a heavier match bullet then the 55's. Has anybody had experiance with these rifles and loads?

cheers,

 

[smak_daddy]

I have no experience with IMR 4320 and .223 BUT...

I own a 1/7 twist barrel AR-15. I am shooting 77 grain sierra match kings with 24 grains of varget with great success.

I am pretty sure your xcr is a 1/9 twist. I have no idea what your SL8 barrel twist is. You may be able to get away with shooting the 77's with your 1/9 twist. But they may be too long.

From my experience, rifles with a 1/9 twist love 69 grain SMK's with 24 - 24.5 grains of varget.