12 Gauge Snap Cap - Set of 2 A Snap Cap used in an empty chamber allows for the safe release of the firing pin or dry-fire. Firing on an empty chamber can result in damage to the firing pin. They also serve to relieve pressure on the firing pin spring when the chamber is closed and the trigger is pulled. Made from solid aluminum, they include a brass, spring loaded primer to safely absorb the force of the firing pin and prevent damage. As a safety feature, each are color coded and stamped with the appropriate gauge RED = 12 GAUGE