(adj.) When applied to revolvers, a gun which must be manually cocked before firing each shot. Examples of single action revolvers include the Colt "Peacemaker," and the Ruger Blackhawk. In reference to semiautomatic pistols, "single action" means that the gun must be cocked before firing the first shot. The gun is then cocks itself for each subsequent shot. The Colt M1911A1 and Browning Hi Power are single action pistols.