Radical Firearms 8.5-inch HBAR 300BLK MIL-STD Upper 7-inch-RPR Features: The Radical Firearms 8.5 HBAR profile 300BLK is a complete MIL-STD upper ready to drop on any MIL-STD lower Receiver. Perfect for the novice or advanced shooter wanting to finish out that build and hit the range. Built with our 7 RPR free float rail system for increased accuracy and keeping your hands cool. No matter what your style of shooting is Radical Firearms has you covered. Radical Firearms 8.5-inch HBAR 300BLK MIL-STD Upper 7-inch-RPR Specifications: Barrel Length: 8.5 Gas System: Pistol Length Barrel Profile: HBAR Profile Barrel Material: 4140 Chrome Moly Vanadium Barrel Finish: Melonite Muzzle Thread: 5/8x24 Chamber: 300BLK Twist Rate: 1:8 Barrel Extension: M4 Feed Ramp Gas Block Type: .750 Low-profile Gas Block Muzzle Device: A2 Flash Hider Upper Receiver Material: Forged 7075 T6 Upper Receiver Style: M4 Mil-Std Upper Receiver Finish: Type III Anodizing Forward Assist: Yes Dust Cover: Yes Handguard Type: Free Float Handguard Style: M-Lok Thin Rail Handguard Length: 7 Charging Handle: Mil-Std Bolt Carrier Group Included: Yes BCG Finish: Nitride