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Banshee 300 Pistol
Mk9, 9mm, 9mm RDB, 9mm (Colt)


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CMMG is temporarily halting the sale of complete firearms, upper receiver groups, lower receiver groups, and Radial Delayed Blowback BCG kits on our website in order to focus on outstanding orders. We apologize for the inconvenience and appreciate your patience as we traverse this extremely busy time. Sign up for notifications on your favorite products to get notified when they become available again or find a local dealer on our dealer page.

Pistol, Banshee 300, Mk9, 9mm Radial Delayed Blowback™, Pistol Tube

As CMMG’s oldest 9mm platform, the Mk9 is continuing to go through changes to become even better than before. Introducing, the new and improved Mk9, now utilizing CMMG’s patented Radial Delayed Blowback™ operating system. Radial Delayed Blowback guarantees less felt recoil for the shooter, offering a more enjoyable shooting experience.  Our Mk9 platform is designed to use Colt SMG-style magazines and is offered in both BANSHEE and RESOLUTE configurations.   

CMMG has made a small modification to 9mm barrels in order for them to be compatible with Mk9 lower receivers. This modification only applies to Mk9 platform lower receivers and does not positively or negatively affect functionality of the barrel with a MkGs, Mk4 or Mk17 platform lower receiver. Barrels that are stamped “9mm Luger” will be compatible with an upgraded Mk9 lower receiver. If your barrel is marked “9x19 NATO”, you will need to purchase a new 9mm barrel in order to ensure reliable function.

Technical Specifications

Platform Mk9
Caliber 9mm, 9mm RDB, 9mm (Colt)
Operating System Radial Delayed Blowback
Barrel Length 5
Barrel Twist 1:10
Barrel Contour MT
Barrel Material 4140CM, SBN
Barrel Twist 1:10
Muzzle Device Thread Protector
Muzzle Thread 1/2 X 28
Gas Port Location N/A
Gas Block N/A
Upper Receiver Forged 7075-T6 AL M4 type upper
Lower Receiver AR15 type lower with Colt patterned magwell
Hand Guard CMMG RML4 M-LOK
Finish Cerakote Standard
Charging Handle CMMG ZEROED Ambi Charging Handle AR15
Pistol Grip Magpul MOE
Receiver Extension CMMG Pistol Extension
Trigger Type Mil-Spec Single Stage
Trigger Guard Magpul MOE
Safety Selector Ambi
Magazine ASC 32rd
Weight 4.7

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