Incorporating fixed sights and a round-butt frame, and available in .357 Magnum,1980 .Speed-Six was intended for use by plainclothes detectives and others desiring a more concealable handgun The .357 Magnum, two and three quarter inch barreled version was the agency issue sidearm to Special Agents of the former Immigration and Naturalization Service, until the agency adopted a .40 caliber semiautomatic pistol in the mid 1990's.[10] The .357 Magnum version was standard issue for the Royal Ulster Constabulary, who, unlike most police officers in the United Kingdom, were routinely armed, but was phased out in 2003 and replaced by the Glock 17, with 15 examples continuing to be issued as duty weapons in 2012.[11]