Use of a snap cap prevents firing pin breakage often caused by "dry firing" during practice or when wanting to remove spring tension from the firing pin or hammer. Don"t think a fired cartridge can do the same because once the primer is indented, there is no more cushioning effect. In these well made snap caps, when the solid brass "primer" is hit, it moves forward against spring pressure to cushion the firing pin so it does not slam against steel. With today"s high gunsmithing prices, a broken firing pin can be very expensive. Protect yours with a quality snap cap. These are not made in some Third World country either, but are first rate European quality. Also excellent to illustrate flinching so it can be corrected, just mix one in with live rounds, and a flinch will be obvious. Sold in package of 2 ea.