Go back & read the first sentence of FlyFish's post above. Eyes & ears, ALL THE TIME. Pistol shooters, take a look at your pistol while holding it up towards a light. Move the pistol & your head around a little. See any light coming through anywhere? That's the same place a particle of burning powder can travel to reach your face or eyes. FROM EXPERIENCE --
one shot, one time, absent-mindedley forgot to put my glasses back on. Felt like I had been stabbed in the eye with a white-hot ice pick. It was a few minuteds of flushing my eye out with running water before I was reasonably sure that I was not BLINDED in my right eye. It was as red as a '59 Ford tailight though.
Steel targets will also return STEEL BB's from air rifles back to the shooting position with about the same velocity that they left. NO STEEL BB'S AT STEEL TARGETS, EVER!!!