Stock Photo - Gunlock (Percussion), Percussion lock with brass housing and iron mechanism, rooster and mounting bolt. It must be mounted lengthwise against the right-hand side of the lock elevation and has a vertical mounting bolt and a cam at the bottom for this. The hammer is pulled down with a chain that runs forward through an eye, while a cam on the left side of the lock pushes it to the left, once below, the hammer is pushed back to the right by a spring, this is to prevent the hammer from being hit back violently by the flame from the zundgat when fired., anonymous, Karlberg Palace, 1830 - 1834, iron (metal), brass (alloy), rope, h 12.8 cm × w 11.7 cm × d 5.8 cm