Pistol firing mechanism. Artwork sequence showing how a bullet is fired from a pistol or similar firearm. At top, a cartridge containing a bullet is shown loaded in the firing chamber. At centre, the firing pin strikes the cartridge, triggering the explosion that propels the bullet (red) out of the pistol's barrel (right). The spent cartridge recoils (white arrow) against a spring that absorbs the force. Smoke is also produced due to the combustion of the explosives. At bottom, the spring-loaded cartridges underneath the firing chamber rise upwards (white arrow), pushing the spent cartridge outwards to leave a live cartridge in the chamber for the next shot to be fired.