| Platform | Mk4 |
| Caliber | .300 BLK |
| Operating System | Direct Impingement |
| Barrel Length | 16.1 |
| Barrel Twist | 1:7 |
| Barrel Contour | MT |
| Barrel Material | 4140CM, SBN |
| Barrel Twist | 1:7 |
| Muzzle Device | CMMG ZEROED Muzzle Brake |
| Muzzle Thread | 5/8 x 24 |
| Gas Port Location | Carbine |
| Gas Block | 0.750 Non-Adjustable |
| Upper Receiver | Billet 6061 T6 Aluminum |
| Hand Guard | CMMG EML15 M-LOK |
| Finish | Cerakote Standard |
| Charging Handle | CMMG ZEROED Ambi |
| Weight | 4.1 lbs |
| Length | 25" |
Due to high demand and supply chain issues affecting many industries, some of our parts and accessories may be on backorder and have an extended lead time. Items currently on backorder can still be purchased and can typically be shipped within 25 business days.
UPPER GROUP, RESOLUTE, Mk4, 300BLK, 16.1"
Originally created for use in subsonic/suppressed applications, .300 BLK has evolved into a very capable caliber, available in a variety of subsonic and supersonic loadings. Whether it’s hunting, personal defense, or target shooting, this .300 BLK RESOLUTE® Upper Group is just the thing to finish your next carbine build. This upper is designed to work with any standard AR15 lower. 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
We aim to please, that’s why every CMMG product is backed by our Lifetime Quality Guarantee against material and workmanship defects. Learn More.