Panki said:
AR Bullets do not shoot through heads like in a movie, small entry, small exit. The entry hole is somewhat small, but the exit hole looks like the bullet had the size of a watermelon.
Depends on the caliber of the bullet and the type of bullet too, a 7.62 FMJ would probably just make a clean exit, but a hollow point would blow a hole in the back of the head. Ive seen other pics though of even 5.56 doing damage like in some of those pics to bodies, mostly from LMGs though, so I would assume its multiple bullets that cause the bulk of the hole.