The Angstadt Arms UDP-9 is an AR-15-pattern semi-automatic pistol-caliber carbine chambered in 9mm that uses a standard Glock 17/19 double-stack magazine feeding directly into an AR-lower-profile receiver. The UDP-9 uses a direct-blowback action with a proprietary bolt carrier group sized for 9mm. AR-15 pistol grips, stocks, and upper receivers are compatible. Type: Rifle Action: Semi-Automatic Caliber: 9mm Capacity: 17 Year introduced: 2016, USA Weight: 88 oz Overall length: 34" Status: Active Intended use: sporting, home_defense, competition