My M16 failed NEW right out of the crate and never got a round thru it... got in trouble when I told Sargeant to get me a 12 gauge.
Sure the M16A1 I had in Basic required a lot (and I mean a lot) of babying to keep it firing, but the A2 I had at all of my permanent duty stations worked fantastic, no matter how much I abused it. The M249s that I used worked great, when belt fed, but heaven forbid you stuck a magazine in the side of it! I was lucky to get off 2 rounds before it jammed.