Yeah but with all the other noise on the battlefield, who could hear the clip ejecting?
M-14 is an excellent weapon, accurate at long range, durable, but too heavy, too big and restrictive as to the amount of ammo to be carried. Nearly impossible to fire accurately on full auto.
A great weapon on the target range, in combat not as effective as the new crop of assault rifles which replaced it as the primary infantry weapon in US formations.
Oh wait I forgot to address the original question of the thread. How did the US win with all of its shortcomings? simple God was on its side.