Combining carbine-like ballistic performance and compact size this 8" BANSHEE(TM) upper group is what you need for the ultimate 9mm AR. Not only does this 9mm upper utilize CMMGA(R)'s radial delayed blowback technology but shooters also have a number of lower/magazine pairing options. 9mm Radial Delayed Blowback uppers are designed exclusively to work with CMMG MkGs Mk17 or mil-spec AR15 lowers using our 9mm Conversion Magazines. Available in different Cerakote finishes all CMMGA(R) Upper Groups come complete with bolt carrier group and ZEROED(TM) accessories including:Features: Platform: Mk4 Mk9 Mk17 MkGs Caliber: 9mm Operating System: Fixed Ejector Radial Delayed Blowback Barrel Length: 8 Barrel Twist: 1:10 Barrel Contour: MT Barrel Material: 4140CM SBN Barrel Twist: 1:10 Muzzle Device: CMMG ZEROED Linear Compensator Muzzle Thread: 1/2 X 28 Gas Port Location: N/A Gas Block: N/A Upper Receiver: Billet 6061 T6 Aluminum Hand Guard: CMMG EML7 M-LOK Finish: Cerakote Standard Charging Handle: CMMG ZEROED Ambi Weight: 3.0 lbs Length: 16.5"