I just wanted to share this little tidbit: So...this is a DPMS upper, mated with a comple, factory (older 4+ year) Bushmaster lower. BCG is from Joe Bob Outfitters. I got the BCG in the mail today. It was so tight, that I had to nearly pry the bolt to make it rotate inside the carrier. After I got it to the forward position, I slid it into the DPMS upper that I purchased @ a very good deal. Once it was inserted, I took a Pmag loaded with 19 rounds of Wolf 55gr and dumped them all blindlessly into the night (into a creekbed on my property). They all went downrange without a hitch. Honestly, I was quite surprised. With as tight as the bolt was, I honestly thought I'd have some malfunction of some sort. However, it didn't happen. This is close to my 17th-21st build; it is nearly as cheap as I've gone. I've seen others who preach and preach, (not going to go into what the sermon contained) yet I am successful. Is it luck? Who knows? I just wanted to share that even with a few dollars invested, repitious fire can still be acheived. Oh...and about BCM -- I reckon there was none, so maybe this didn't happen???