Caliber 5.56 NATO - Barrel 16 1:8 Twist - Weight 7 lbs. - Upper Receiver Forged 7075 T6 Aluminum Type 3 Hard Anodized Black - Lower Receiver Forged 7075 T6 Aluminum Type 3 Hard Anodized Black - Hand Guard 15 M-LOK - Thread Pattern 1/2-28 - Muzzle Device A2 Flash Hider - GAS Block .750 Diameter - GAS System Low Profile Carbine Length - Buttstock 6 Position Carbine Buttstock - Buffer Tube 6 Position Buffer Tube - Bolt Carrier Standard M16 Profile - Charging Handle Standard - Pistol Grip A2 Style - Safety Ambidextrous