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 “9×19 NATO”, you will need to purchase a new 9mm barrel in order to ensure reliable function.