The Smith and Wesson Model 39 was a semi-automatic pistol developed for the US Army service pistol trials of 1954. After the Army abandoned its search for a new pistol, the Model 39 went on the civilian market in 1955 and was the first of Smith & Wesson's first generation semi-automatic pistols. Used by the Illinois State Police and the US Navy SEALs, it was a groundbreaking pistol for use with the military and law-enforcement agencies.