DPMS DP51655120178 Barrel Length: 16″ Barrel Material: 4150V Chrome Moly Vanadium Steel Barrel Finish: Phosphate Barrel Profile: M4 Chamber: 5.56 NATO Twist Rate: 1 in 7″ Extension: M4 Gas System: Carbine-Length Gas Block Type: Low Profile .750″ Diameter Upper Receiver: Forged 7075 T6 Aluminum Receiver Style: M4 Flat top with feed ramps Receiver Finish: Hardcoat Anodized Forward Assist: Yes Dust Cover: Yes Handguard Style: PSA 13.5″ Lightweight M-Lok Free Float Rail Bolt Steel: Carpenter 158, Mag Phosphate coated Bolt Carrier Steel: 8620, Chrome Lined Staked Gas Key: Yes Lower Receiver: Forged 7075 T6 Aluminum Receiver Finish: Hardcoat Anodized Fire Control Group: PSA AR-15 Mil-Spec Fire Control Group Buffer Tube: 7075 T6 Aluminum Mil-Spec Tube Adjustment: 6-position collapsible Stock: PSA Classic Carbine Stock Magazine: (1) 30-Round Magazine (where available by law) Weight: 7 Lbs Length: 32″