The MPX is SIG Sauer's 9mm pistol-caliber carbine, designed to fill the role of the HK MP5 with a more modern piston operating system and AR-15-compatible controls. A rotating-bolt, short-stroke piston design in 9mm, the MPX uses proprietary double-stack magazines and a fully ambidextrous control set. It has been adopted by USSS, FBI SWAT, and numerous federal and municipal SWAT teams as a less-lethal-overpenetration alternative to rifle-caliber weapons. Available as a rifle, SBR, and pistol. Type: Rifle Action: Semi-Automatic Caliber: 9mm Luger Capacity: 30 Year introduced: 2015, USA Weight: 6.75 oz Overall length: 32" Status: Active Intended use: law_enforcement, duty, competition