My son is in the army and has been in Iraq for a few months. Four weeks ago he was on patrol with several others. Two men jumped out of a car. The first started filming with a camera, and the second got out with a rifle and shot my son in the back of the head. The helmet stopped 99% of the impact and he only recieved a deep gash and a concusion.
The shooter got away.
My son is a pretty big guy. When he got hit, my son thought one of his buddies had hit him from behind trying to goof around and he was mad. When he turned around and saw nobody was close to him he realized he had been shot. That is when he felt the blood running down his head, he shouted that he was hit and ran for cover.
They took his helmet to study it, but he is supposed to get it back to keep.