Nope. It will chamber. From the magazine. I did that test without the firing pin because of the live rounds I was using. The m16 is a push feed system. The extractor is not in control of the round until the bolt is fully in battery. This necessitates the feedway be as conducive as possible to smooth travel. If you doubt this, take any quality built (most factory gus don't count) m16 upper and hold the muzzle down with the reciprocating components removed. Drop a live round in the back. Bet it ends up in the chamber. Dump it back out. Repeat if you like. Now, strip your bolt and firing pin from your carrier. Install the carrier in the upper. Reassemble onto the lower. Insert a mag. Rip the charging handle and let it fly. It will chamber. If you REALLY want to, do it the way the guy in the OP pic did. In your rifle, not mine.So the only way this could have happened is if the idiot had a chambered round removed his BCG and removed the bolt and put the Bolt Carrier back in on an already chambered round
it's a rifle I spent a lot of time building. I don't want to do what this dipshit did with a live round. A cut down 20" FN barrel reduced to 16", I upsized the gas port and reinstalled the FSB to make a true dissipator. Some other things done in the upper like cleaning up the barrel extension for slicker feeding. On a postie lower, it's a Singer sewing machine. On a semi lower with a Jewell trigger, it's almost as fast.