I was watching the show, BONES, on Hulu and right before the third commercial, Booth pulls his gun on another agent.
IT WAS THE GUNCRAFTER'S 50 CAL !!
Go here and you will see the slide and look at the barrel hole. That ain't no .45! (just about 23:10)
Hulu - Bones: The Man In The Morgue - Watch the full episode now.