Proof Pyle wass a complete moron.

His name was Leonard Lawrence.

i think you missed the point that all these things he went through made him into a killer.

How is any recruit supposed to shoot anyone when they don;t have access to ammunition until they have been in training for a while?

You might have noticed that while practicing with the M-14 at the rifle line, Private Leonard removed a partially filled magazine of ammo, then inserted a fresh magazine. All he needed was two rounds to kill Gunnery Sergeant Hartman and then himself.