We did a live fire move and cover n army basic in 81.
We had live fire in training in 65, we were crawling through a obstacle course with a machine gun firing over us (later I saw it was set up to fire way over a standing person). It gave us an idea what it sounded line to be down range.
Also, on the range at that time they had people in trenches that after firing at targets they would pull the targets down and mark where they were hit. Not sure if they still do this.
So, accidents can happen.
We also practiced with live grenades.
War is dangerous, training for war can be just as dangerous.