A bullet fired form a gun is not released. It is ejected out with the subsequent shot. It is known as:

D i.e. Tandem bullet Tandem or Piggyback bullet are the two(2) bullets ejected one after the otherQ, when the first bullet having been stuck in the barrel, fails to leave the barrel & is ejected by the subsequently fired bullet. The bullets may separate within the body or before they hit the target. Tracer bullet leaves a trace or visible mark in path (or flight) so that a person (gunner) can observe the strike of a shotQ.