Originally Posted by
JustDSM
I'll be heading back to the range today with this easy change...
As per the many replies about this, it's something I'll look at, but before I pick up a standard auto carrier I'll work with the enhanced carrier for now since I have it for one. I'd have to buy an auto carrier.. When I spec'd the parts for this upper it was heavily influenced by the reviews of folks like Grant and IG and how this system works on a SBR using a variety of ammo in both suppressed and unsupressed applications. *Note: Issues were all being fired unsuppressed, I'll run it suppressed once I can iron out issues when firing without the can.
This reply got me thinking. The malfunctions looked as if the casing was "slipping" or being ripped off the extractor. Initially I thought that I was looking at an over-gassing problem since it appeared that the BCG was potentially moving too quickly causing the issue. That quickly faded in theory of the extractor spring not being able to keep pace, but when I got home and cleaned things up, The extractor has the insert, spring, and at that time the o-ring. However, what was observed was the spent casing 3/4 of the way (give or take) extracted but the round being stripped from the magazine being fed up into the spent casing still occupying that real estate. It's clear the spent casing and extractor "went separate ways" and on the return trip the bolt picked up the next round. Just wanted to make sure everyone was clear on that. The rifle was getting enough gas to cycle the BCG. It RELIABLY locked back every time on empty mags.
If problems persist I'll go to a standard auto carrier, but I'm not convinced at this point the issue lies in the carrier. At this point I'm more suspect of the bolt/extractor. In regards to the gas block/port. I didn't feel the need to measure the port as BCM's reputation isn't one I would typically question. However in the event this can't be resolved I wouldn't be opposed to looking into this. Just for the sake of complete disclosure, the gas block is set screw, and is aligned with the dimple in the barrel. I confirmed it's orientation last night, and there was no evidence of gas leakage.
"Miil-spec shot-peened, AR15/M16 9310 bolts. Manganese phosphate treated & MP inspected."
I also trust Rainier,