Revolver many European gun-makers, in numerous designs and configurations. However, these weapons were difficult to use, complicated and prohibitively expensive to make, and as such they were not widely distributed. In 1836, an American, Samuel Colt patented the mechanism which led to the widespread use of the revolver, the mechanically indexing cylinder. According to Samuel Colt, he came up with the idea for the revolver while at sea, inspired by the capstan, which had a ratchet and pawl mechanism on it, a version of which was used in his guns to rotate the cylinder by cocking the hammer. This provided a
History of the New York City Police Department standard issued revolver for the NYPD. It was the Colt New Police Revolver in .32 Long Colt caliber. He also instituted required firearms training including pistol practice and qualification for officers. In 1907 the Colt Police Positive revolver in .38 caliber was adopted by the department. In May 1926 the NYPD adopted the .38 Special cartridge as the standard issue ammunition for the department and started issuing its officers the Smith & Wesson Model 10 revolver and the Colt Official Police revolver. In 1994 the NYPD replaced the revolver as its main service weapon and adopted the 9mm semiautomatic pistol