I carried 1,000 rounds with both the M-14 and M-16 rifles. When I took over the M-60, I still carried almost 1,000 rounds in four belts. I also had everyone in the platoon carry 400 rounds. Talk to any soldier or Marine, and they'll tell you they won't run out of bullets in a firefight. "When in doubt, empty the magazine". is still practiced today in Afghanistan, though in three-five round bursts.