The Stag 15 M4 Upper offers the high quality, durable, military proven M4 design you've been looking for. Made to mil-spec standards, this upper satisfies the need for a standard GI carbine. Featuring a 5.56x45mm NATO chamber 16" 1/7 chrome lined barrel with a thermoplastic handguard and A2 birdcage flash hider.This upper half does not include a BCG or Charging Handle.Action: Semi-Auto Direct ImpingementCaliber: 5.56 NATO | .223Twist Rate: 1/7 Button RifledMuzzle Device: A2 Flash HiderBarrel: 16", 4150 Steel, Chrome Lined, Government Profile, Manganese Phosphate CoatedHandguard: Thermoplastic with Double Heat ShieldsReceiver Material: Forged and Mil-Spec 7075 T6 Aluminum with Type 3 Hard Coat AnodizingBolt Carrier: NoneGas System: Carbine Length with A2 Front PostCharging Handle: None