Beaumont-Adams revolver

The Beaumont-Adams revolver is a black powder, double action percussion revolver made in London by Robert Adams, improved by Lieutenant Frederick Beaumont, who patented a mechanism in 1855 that let the gun fire either single action or double action. The improvement gave it an edge over contemporary Colt revolvers and made it popular with British officers for its stopping power and its faster trigger cocking action. It was formally adopted by the British Army in 1856, with the most common military version chambered in .442 caliber, though the maker also produced .500, .479 and .320 versions. It stayed in British service until 1881, when the Enfield Mark I revolver replaced it, and it also saw use worldwide, including during the American Civil War and various colonial conflicts.