The Windham MPC (Multi-Purpose Carbine) is Windham's M4-configured AR-15 with a flat-top receiver, M4-profile 16-inch chrome-lined barrel, and a four-position collapsible stock. Windham's attempt to replicate the M4 configuration for civilian use. Type: Semi-Auto Rifle Action: Gas-Operated Caliber: 5.56x45mm Capacity: 30 Year introduced: 2015, USA Weight: 6.9 oz Overall length: 32.6" Status: Active Intended use: Home Defense, Patrol, Range