High capacity magazine failure to feed correctly has been noted in some of these tragedies, but the M16's action was prone to jam if not kept scrupulously clean.
IIRC, they initially also used the gunpowder originally intended for the 7.62 mm NATO round instead of the originally recommended gunpowder for the 5.56 mm ammo. They had different burning rates. The gunpowder for the NATO round took the heat initially for a design that's prone to getting dirty. My M16 extractor retaining pin broke on me over 40 years ago at just the wrong time.
I preferred 20-round magazines for fire-and-maneuver exercises in scarce, low cover situations in the field. Only training experience, but never got zapped in 7 years while playing with our fancy (expensive) laser tag gear (avoiding public use of service acronyms here). Well, 6 years (REMF heavy unit misnamed “combat” for the last year of 7).