Flintlock, a firing mechanism used on early firearms. It was first used on muskets about 1650, later on pistols. The cock, or hammer, of the flintlock held a piece of flint which, when the trigger was pulled, struck a piece of steel and caused sparks to fly. The sparks ignited a small priming charge of powder in a pan, which was uncovered as the flint struck the steel. The fire flashed through a touchhole, exploding the main powder charge and discharging the ball (bullet). By about 1850 flintlocks had been replaced by percussion locks.