I've gotten and still have bolt carriers with no MPI markings. No shot peening. etc etc. They run fine and I'll put em up against anything out there. I've got a BCM chrome plated bolt with a plane bolt carrier made back when BCM was a new company and its not got any of the GI spec bullcrap about it and it has several thousand rounds under its belt. I've also got, CMT bolts, LMT enhanced bolts, and I just bought a Nickle Boron coated bolt by Fail Zero. I got it because I wanted an easy to clean bolt and also because the dealer couldn't move it because it wasn't a full auto bolt carrier--it was the AR 15 carrier and nobody wanted it. So I told him to make me a deal as he really wanted to get it off the shelf and I picked it up for $180. I could give a crap about a full auto bolt carrier. Doesn't mean anything in semi-automatic rifle. That 1/2 ounce of metal difference doesn't do squat for the rifle.
So here's my EXPERIENCE with the nickle boron coated bolt based on owing a half a dozen other garden variety and enhanced bolts. First, it functioned flawlessly in a new build I completed last week through the first 150 rounds. Second, it headspaced correctly in a PSA barrel I installed in the gun--checked it with a USGI Field Guage. Third, I can't believe how easily the thing cleans up. All the other bolts I own--even the LMT enhanced bolts, get cruddy and gunked up with carbon and it takes some scraping to clean them off. The Nickle Boron bolt will literally wipe clean with a rag.
I like it. It makes cleaning a breeze. Its also the slickest bolt I've got in any of my guns including some with a couple of thousand rounds down the tube.
I'll need more trigger time with this BCG to give it my full endorsement but its a winner for me so far! If I was looking to trick out my AR this wouldn't be the first thing I'd spend money on--without exception I'm sticking a Giessele SSA trigger in the gun first. Then will consider other upgrades. But it would be up there on the list based on what I've seen so far.
“Est Nulla Via Invia Virute”
Last edited by Big Bird; 10-10-2012 at 19:49..