I had a partial case head separation using a 1.8oz buffer

[LRRPF52]

I went back to the OP and I still think this is early unlock.

An additional detail dawned on me when researching the barrel itself... I can't seem to find it sold and not include an adjustable gas block. This seems to reinforce my suspicion of early unlock since the port diameter may be oversized with an expectation that the gas system would be appropriately adjusted.

I started looking up Odin Works 12” 6.5 Grendel barrels as well, and also noticed that they do come with their adjustable gas block:

I’m not finding any fault with them just for clarity.

That port doesn’t look particularly large, but I obviously don’t have it in-hand.




I do know that with the 12” Grendels I have built, which have at least many hundreds of rounds through them so far, 99% suppressed, they used .068” gas ports if I recall, whatever we spec’d with the Group Buy through Faxon. I still dial the gas down on the Bootleg carriers (no affiliation), mainly because I’m shooting suppressed.

For the few rounds I shot in 2018 unsuppressed, I didn’t notice any issues with the brass, and cyclic rate felt about as in the happy space window as I’ve felt with an AR-15 in a long time.

Extra power action/recoil springs played a role in that, which would also fight early extraction.

Now I’m wondering what action spring and carrier weight the OP used.