The Radical Firearms 16" Socom 5.56mm AR rifle uses MIL-STD Upper and lower receivers along with our 15" FCR free float rail system for increased accuracy, keeping your hands cool, and giving you plenty of room for accessories. Regardless if it’s your first or fiftieth, a Radical Firearms AR rifle will not disappoint! Barrel Length: 16" Barrel Material: 4140 Chrome Moly Vanadium Barrel Finish: Melonite Barrel Profile: Socom Barrel Thread Pitch: 1/2x28 Chamber: 5.56/ 223 Rem Twist Rate: 1:7 Barrel Extension: M4 Feed Ramps Gas System: Carbine Length Gas Block Type: .750 Low Profile Gas Block Muzzle Device: A2 Upper Receiver Material: Forged 7075 T6 Upper Receiver Style: M4 Upper Receiver Finish: Type III Anodizing Forward Assist: Yes Dust Cover: Yes Handguard Type: Free Float Handguard Style: M-Lok Thin Rail Handguard Length: 15" Charging Handle: MIL-STD Lower Receiver: Forged 7075 T6 Lower Receiver Finish: Type III Anodizing Fire Control Group: MIL-STD SYLE AMBI Buffer Tube: CARBINE MIL-STD Stock Adjustment: 6 Postion Stock: MFT MINIMALIST Magazine: 30 round