Its a shotgun blast with no pumps or anything extra.
A 45 Smith & Wesson pistol shot. Recorded with a Zoom H2.
1903 Springfield .30-06 Gun Fired in a small intimate 535 seat theatre. Some Noise Reduction applied afterwards
A gun cocking sound perfect for larger guns! Also check out: http://freesound.org/people/woodmoose/sounds/155388/ if you're looking for a smaller gun cocking ...