Specifications: PLATFORM: MK4 CALIBER: 5.7X28MM OPERATING SYSTEM: RADIAL DELAYED BLOWBACK BARREL LENGTH: 16.1 BARREL TWIST: 1:9 BARREL CONTOUR: MT BARREL MATERIAL: 4140CM SBN BARREL TWIST: 1:9 MUZZLE DEVICE: CMMG ZEROED MUZZLE BRAKE MUZZLE THREAD: 1/2 X 28 GAS PORT LOCATION: N/A GAS BLOCK: N/A UPPER RECEIVER: BILLET 6061 T6 ALUMINUM LOWER RECEIVER: MK4 FORGED 7075 T6 HAND GUARD: CMMG EML15 M-LOK FINISH: CHARCOAL GREEN CHARGING HANDLE: CMMG ZEROED AMBI PISTOL GRIP: CMMG ZEROED PISTOL GRIP BUFFER TYPE: CARBINE RECEIVER EXTENSION: CMMG 6 POSITION FASTBACK EXTENSION STOCK / BRACE: CMMG RIPSTOCK TRIGGER TYPE: MIL-SPEC SINGLE STAGE TRIGGER GUARD: CMMG ZEROED TRIGGER GUARD SAFETY SELECTOR: CMMG ZEROED 60/90 DEGREE MAGAZINE: 32RD WEIGHT: 6.4 LENGTH: 32.8"