My very first semi-automatic pistol was the 2nd generation S&W Model 645 chambered in .45ACP. She has a target trigger and target sights ( WO RR ) and holds 8+1. The stainless steel frame and slide sport an ambidextrous safety/decocker, a squared trigger guard, and black plastic grip plates, which I replaced with Pachmayr's.
S&W began experiments with .45ACP firing pistols in 1984, and produced their first one, the Model 645, in 1985. Public demand led to the development of this series. The series consists of normally double-action weapons, or what Smith & Wesson refers to as a traditional double action. They generally have a barrel bushing press fitted into the muzzle end of the slide instead of a separate barrel bushing like a 1911 pistol. Like many Smith & Wesson models, each variant was generally in production for only a few years. (The Model 645 was introduced in 1985, and produced until 1988.)
The S&W 645 was used in seasons 3 and 4 of the TV series Miami Vice by the main character Vice Detective Sonny Crockett.