The guy shot in the head did not have a gapping whole in his skull like what I’d imagine a 223 or 5.56 would leave. See the arm of they guy he shot for reference. The head shot may have been from a small caliber pistol.
Maybe. The cranium can. Obtain some of the hydrostatic damage , I imagine. Haven’t heard any specifics on entrance/ exit wounds. 5.56 (assuming that’s the round) is somewhat frangible.
How did the arm shot guy retain grip of his pistol?