I thought the other problem was that since the design was rushed, the chroming was inadvertently left out of the design, and when pointed out, the McNamara’s whiz kids referred back to the rushed design specs.
The main problems with the M-16 in Vietnam were the case head separation jams and inaccessibility of the chamber. The cases would stick in the chamber and the extractor would tear the whole rear part of the cartridge way, leaving the rest of the cartridge case on the chamber. The next round was fed right Ito it, fusing the mess together.
So there you are, fighting for your life, and you have remove the magazine, knock out the rear pin, open the receiver, remove the bolt and bolt carrier - the use an assembled cleaning rod to knock the mess in your chamber out of the weapon. Then you had to reassemble everything and slam in a new magazine, chamber a round and pray it didn’t do it again.
A lot of good men died by their broken M-16s over there. They tried blaming it on us back then but long after the war, some truth came out.
I got my M14 back and kept it. If by some freaky chance a cartridge stuck in a ‘14, you could reach it with a knife blade.