Refers specifically to the striking mechanism of a firearm. Compare with 撃鉄 (げきてつ), which is a more technical term for the same part.
See also: 撃鉄
Cock the hammer of the pistol.
striker; fire striker
Compound of 打ち (uchi, 'striking') + 金 (kane, 'metal'), referring to the metal striking part of a firearm.