| Platform | Mk4 |
| Caliber | .22 ARC |
| Operating System | Direct Impingement |
| Barrel Length | 20 |
| Barrel Twist | 1:7 |
| Barrel Contour | MT |
| Barrel Material | 4140CM, SBN |
| Barrel Twist | 1:7 |
| Muzzle Device | CMMG ZEROED Muzzle Brake |
| Muzzle Thread | 1/2 x 28 |
| Gas Port Location | Rifle |
| Gas Block | Adjustable 0.750" |
| Upper Receiver | Billet 6061 T6 Aluminum |
| Hand Guard | CMMG EML15 M-LOK |
| Finish | Cerakote |
| Charging Handle | CMMG ZEROED Ambi |
| Weight | 4.7 lbs |
| Length | 28.9" |
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, ENDEAVOR, Mk4, 22 ARC, 20"
5.56mm is tried and true, but 22 ARC brings 22-250 performance to the lighter-weight AR15 (Mk4) platform, and the ENDEAVOR® Mk4 upper group with its 20" barrel is sure to extract all the ballistic performance you need.
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.