what angle was the bullet fired?

I'd suspect that the caliber - the loading of the bulltets (propellent
and bullet weight and shape) would have influence onn the outcome as
well ~ to answer your question.

extra credit question --

Five carefully measured and placed, 50 if placed haphazardly. This
also depends on the dificulty of the location of rivets to be
installed.

Bryan "The Monk" Chaisone