The M16 was issued w/o proper training and inadequate cleaning supplies. Combined with the humid jungle of Southeast Asia, this caused problems and the rifle gained a bad reputation. Because tolerances were tighter than in previous military arms, the M16 had to be kept extremely clean. War correspondents filed reports where the M16 was jamming, and many were shown on the evening news. It was reported that our soldiers were being killed by a faulty rifle.

This led to Congressional investigations which turned up two related problems. First, the cleaning issue. As training was provided, supplies issued, and some redesign, M16 performed more reliably. The second issue dealt with the use of ball propellants instead of IMR propellants. Remington had developed the 5.56mm round using one type of powder, but the specification was changed during military contract production to allow an alternate. This powder caused more fouling and increased the rate of fire.