Introduced to the firearms market in 1927, the Colt Official Police is a medium frame, double-action revolver with a six-round cylinder, primarily chambered for the .38 Special cartridge, and manufactured by the Colt's Manufacturing Company. The intended specific target market for the Official Police was mainly law enforcement agencies and it became one of the best selling police firearms of all time, eventually in the 1950s coming to exemplify typical peace officer weaponry. The Official Police was also used by various U.S. and allied military forces during World War II.