Finally figured it out, the gas rings on my BCG were shot. Kind of strange since I bought it new from a quality vendor. But I tossed 3 new gas rings on there and it’s been running like a champ now. Thanks for all the help guys!
Learn how to bench test worn gas rings for future smithing.
It did pass the “standing upright on bolt face” test, albeit barely.
The gas key may be leaking. Put some soap around the gas key and blow into it with a straw. If it leaks remove the gas key and reinstall with locktite and really stake the key.
Sent from my SM-N920V using Tapatalk
AiM shipped my Nib BCG with only two out of three rings on the bolt. I was pretty surprised that it was overlooked during “QC”.
If you can only run Tula then it indicates that there is too much gas running through the gas port of your rifle. Tulammo ammunition is notoriously underpowered compared to even other steel cases ammo manufacturers and brass cased ammo as well. It is likely that your barrel has a gas port that is very wide, relatively speaking. Does your rifle have a blue Springco or GI buffer spring? If not getting one could help if you change out for a H2 or H3 buffer. Do not use a carbine buffer as that will not help with the over gassing. Based on your purchase of the gas buster I assume you are waiting on a suppressor. If your rifle will be shot suppressed then you can expect to have an even higher volume of gas reaching the action.
If an H3 and blue Springco do not fix your over gassing issue then it means you either need to invest in a VLTOR A5 buffer system or that you need to replace your barrel with a different 11.5" barrel. Bravo Company USA sells 11.5" CHF barrels that they also sell along with their 11.5" upper receivers. LMT and Daniel Defense sell 10.5" barrels and uppers. Either of those companies should be able to provide you with a functioning product if you cannot get your current set up to work.
Best of luck.
Why would you need to replace your barrel when you could use an adjustable gas block or BRT’s custom gas ports?
http://www.blackrivertactical.com/concrete5/customtune-gas-port/
I’d personally just swap out the barrel or upper. Better than trying to tune a gun unless you are hoping to place better in 3 Gun or you just want something to tinker with. I noticed only after I posted in this thread that the OP already solved the issue.
Thanks for the in depth response! I initially went this route (tried a H2 buffer and higher power buffer spring). Also I was shooting it suppressed with my AAC Cyclone, it would shoot the steel Tula suppressed and unsuppressed, but not the brass cased 5.56 either way.
Thanks for all the help!