M&P15X features a detachable carry handle, a quad-rail handguard, and a 16-inch M4-profile chrome-lined barrel. The X designation signals military-influenced features including the removable carry handle that allows both traditional and optic mounting. Type: Semi-Auto Rifle Action: Gas-Operated Caliber: 5.56x45mm Capacity: 30 Year introduced: 2007, USA Weight: 7.2 oz Overall length: 35" Status: Active Intended use: Patrol, Tactical, Range