| Platform | Mk4 |
| Caliber | 5.56x45mm |
| Operating System | Direct Impingement |
| Barrel Length | 18 |
| Barrel Twist | 1:7 |
| Barrel Contour | MT |
| Barrel Material | 416SS, SBN |
| Barrel Twist | 1:7 |
| Muzzle Device | CMMG ZEROED Muzzle Brake |
| Muzzle Thread | 1/2 x 28 |
| Gas Port Location | Rifle |
| 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 | 4.5 lbs |
| Length | 26.9" |
Expected to ship within 10 business days. Build to Order products are items that are not built but all components are in stock and ready for assembly.
THIS PRODUCT IS BACKED BY THE CMMG LIFETIME QUALITY GUARANTEE.
UPPER GROUP, ENDEAVOR, Mk4, 5.56x45MM NATO, 18"
For those looking to reach out further with 5.56mm, the ENDEAVOR® Mk4 Upper Group is here. Perfect for new builds or for use with an existing AR15 lower receiver, this upper utilizes an 18” 416 stainless steel barrel with a nitride finish for enhanced ballistic performance and superior durability.
Available in seven different Cerakote finishes, every ENDEAVOR Upper Group includes the bolt carrier group as well as a carefully curated selection of parts and accessories including:
ZEROED AR15 Ambi Charging Handle
ZEROED AR15 Polymer Dust Cover
We aim to please, that’s why every CMMG product is backed by our Lifetime Quality Guarantee against material and workmanship defects. Learn More.