Welcome to the mildly insane world of terminal ballistics! The link below may or may not help, but don't ever bet the farm that a bullet won't deflect after striking something/anything. Sure bet that it will, only question is how much.
http://www.rathcoombe.net/sci-tech/ballistics/wounding.html

I am..........disturbed.

Concerning the difference between man and the jackass: some observers hold that there isn't any. But this wrongs the jackass. -Twain