I don't know what set up you are using, but I am fairly certain your gun will run that H4. Call me silly.

I think I am running an H3 with green Springco in my Colt 6920/BCM hybrid carbine and it runs like a champ.

I also run the H4 in my 11.5" and 12.5" unsuppressed and suppressed. 100% reliability.

Quote Originally Posted by RyanB View Post
I ordered an A5H4 (6.8 oz) buffer tonight for my suppressed gun. I'm pretty sure the 1.5 ounces over what I have now is too much but the next step up (6.03 oz) was out of stock everywhere.

Will report back when I can. In any case with M193 I still have way more gas than I need.