Hatcher documents one instance in a revolver. The "bang" came from the cylinder gap. IIRC, there were 6 bullets in the barrel. In frustration the shooter finally threw the gun at the owl which was offending him by keeping him (not Hatcher himself) awake.
Hatcher delves pretty deeply into barrel obstructions of all kinds.
Terry, 230RN
REF:
Aw, go find it for yourself.