The Sigma — S&W's first polymer striker-fired pistol, so similar to the Glock 17 that Glock sued and settled, leading to minor design changes. Type: Pistol Action: Semi-Automatic Caliber: 9mm Luger Capacity: 15 Year introduced: 1994, USA Weight: 26 oz Overall length: 7.24" Status: Discontinued Intended use: Self-Defense