| Caliber | .45 ACP |
| Operating System | Fixed Ejector Radial Delayed Blowback |
| Barrel Length | 16.1 |
| Barrel Twist | 1:16 |
| Barrel Material | 4140CM Nitride |
| Barrel Twist | 1:16 |
| Muzzle Device | Z Muzzle Brake |
| Muzzle Thread | 0.578-28" |
| Upper Receiver | Mk4 PCC Fixed Ejector 6061 T6 Aluminum |
| Hand Guard | EML7 M-LOK |
| Charging Handle | ZEROED Ambi |
| Weight | 3.7 lbs |
AR Parts Notice - State/local restrictions may apply in CT, DC, IL, MA, NJ, NY, or WA. Customers must review our Shipping Policy prior to ordering.
Upper Group, RESOLUTE, FE, .45 ACP, 16.1"
RDB was an advancement from straight blowback. Compact action RDB was an advancement to the original RDB. This (fixed ejector on RDB) is a continued advancement bringing new technologies to the original platform.
With over a century of service across the world, .45 ACP has been the pistol caliber of choice for many shooters. For anyone looking to complete the ultimate pistol caliber carbine, the RESOLUTE® Upper Group chambered in .45 ACP is here. Available in seven different Cerakote finishes, all CMMG® Upper Groups come complete with bolt carrier group and ZEROED™ accessories including:
ZEROED AR15 Polymer Dust Cover
ZEROED AR15 Ambi Charging Handle
MkG Radial Delayed Blowback™ Operating System
Since making its debut on the original .45 ACP MkG platform in 2017, Radial Delayed Blowback has revolutionized pistol caliber ARs across the entire CMMG lineup. As a result of meticulous engineering, Radial Delayed Blowback not only addressed some operational concerns with a traditional straight blowback system, but it also delivered pistol caliber carbines and personal-defense weapons with softer recoil impulses and lighter weight bolt carrier groups and buffer systems than straight blowback systems could deliver. Check out our CMMG Resources article & video to learn more about what sets Radial Delayed Blowback apart.
MkG .45 ACP uppers are only designed for use with MkG lowers, other manufacturers’ lowers may work but CMMG® cannot guarantee function.
We aim to please, that’s why every CMMG product is backed by our Lifetime Quality Guarantee against material and workmanship defects. Learn More.