Sorry taken out of context, Biff talked about his encounter with an enemy aircraft and how close he came to firing, if he did get that one chance I bet he like any one of us would blast away making the most of it whether he was in a P51 or F15.
I know in the era of "Westerns" they always aimed for and hit the shoulder, which with the remarkable medicine of the time always healed perfectly, so much so that it never affected their ability to fire a rifle again.