|Firing pin marks on cartridges. Top, left to right: Spencer cartridge with a Ballard block type firing pin imprint; .50-70 cartridge struck with a Sharp's firing pin. Middle, left to right, Spencer cartridge struck twice; Spencer cartridge with a Jocelyn firing pin imprint. Bottom, left to right, Spencer cartridge struck by a Sharp's firing pin but fired in a Spencer; a standard Spencer firing pin. Photo courtesy of the Texas Historical Commission.