The M400 Tread Coil variant adds a coil-stock design for improved cheek weld and adjustability over standard M4 stocks. Otherwise identical to the standard Tread. A more ergonomic stock option without adding significant cost. Type: Semi-Auto Rifle Action: SA Caliber: 5.56 NATO Capacity: 30 Year introduced: 2020, USA Weight: 63.5 oz Overall length: 32.5" Status: Active Intended use: Tactical, Home Defense