At ROTC summer camp in 1964 I fired a M-1 with no officially supplied hearing protection. However, we all had to have spit shined boots and we shined them using cotton . . .
Geez...can you imagine if you had a concussion in combat, which I have to believe must not have been uncommon, having to fire a weapon or experience nearby explosions?
Apart from the fear and danger of getting killed or maimed, it must have been like have a ball peen hammer whacking your skull from the inside out with every report...