SOF magazine had an article about the M 16 problems, some four or six years ago. No particular with their story and the linked article.
A slight variation on caus-and-effect was that the original use of IMR powder was protested by the Olin Corporation. Olin wanted in on the act, figuring that since Colt was getting paid for rifles, Olin should "contribute to the cause" by selling ammo.
Ball powder leaves more residue than the IMR; it did indeed increase the cyclic rate of fire, and the obduration became a problem.
So greed and politicking led to a bad package; CYA led to any rational solution taking an undue number of years. And so good men died.
There are times, when one considers the apparently increasing instances of this sort, that maintaining a positive attitude about loyalty and patriotism becomes rather difficult.
, Art