tip of the iceberg.
but it's not REALLY like that.
it wasn't JUST ball powder, ball works well in AR's.(H335 is ball)
more of a case of left and right hands not communicating, plus ignorance, arrogance and blind faith in a design that sat untested and unchanged since about 1959.
Armalite sold the rights to Colt in 1959, Stoner moved on to other weapons and the design was "frozen".(ignored/neglected/ridiculed/passed over, take your pick)
Stoner stated before the Ichord committee he found it inconceivable that he (Stoner) could have hit the best bullet/powder combination first time, yet any attempt to change the design was met with "that's not how Stoner wanted it" {AllHail Stoner}
M16's were brand new to everyone, and were touted as self cleaning.(there's a picture i can't find of the tag attached to a SP-1 that states so)
there didn't even EXIST (in the Armed Forces) a cleaning rod small enough to go down the bore, they couldn't be cleaned if they wanted to.
McNamara nixed the chrome bore and chamber to save money.
coupled with a draft Army and terrible conditions in S.E Asia, well...
it's all laid out in TBR, with documentation.