Bullet hole in glass

Question

This is more of a straight forward question, but specifically when a bullet makes warps the glass around the hole, creating outward ‘bubble’ is that the exit or entrance hole
Also, how common of an occurrence is this?

In: Physics

Answer 1

The cone is the exit hole. Look up ‘conchoidal fracture’. Imagine the bullet point pops through a very small area of the first part of the glass but the cracking moves outward as the bullet moves through.