| Platform | Mk4, Mk57 |
| Caliber | 5.7x28mm |
| Operating System | Radial Delayed Blowback |
| Barrel Length | 5 |
| Barrel Twist | 1:9 |
| Barrel Contour | MT |
| Barrel Material | 4140CM, SBN |
| Barrel Twist | 1:9 |
| Muzzle Device | CMMG ZEROED Linear Compensator |
| Muzzle Thread | 1/2 x 28 |
| Gas Port Location | N/A |
| Gas Block | N/A |
| Upper Receiver | Billet 6061 T6 Aluminum |
| Hand Guard | CMMG EML4 M-LOK |
| Finish | Cerakote Standard |
| Charging Handle | CMMG ZEROED Ambi |
| Weight | 2.5 lbs |
| Length | 13.8" |
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, BANSHEE, 5.7X28MM, 5"
Gaining more acceptance as the go to personal defense caliber for many shooters in recent years, 5.7x28mm has proven itself to be well suited for the job. With incredibly flat shooting performance and low recoil, 5.7x28 excels at closer ranges while still providing ideal penetration. Equipped with a 5” barrel, this is the most compact 5.7x28mm upper group CMMG® offers. CMMG 5.7x28mm uppers are designed to work with CMMG Mk57™ lowers or standard AR15/Mk4 lowers (when used with 5.7 AR Conversion Mags). Available in 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
ZEROED Linear Compensator 5.56mm
Radial Delayed Blowback™ Operating System
Originally developed for the .45 ACP MkG platform, CMMG has adapted our Radial Delayed Blowback system across our pistol caliber lineup to create pistols and rifles with a softer recoil impulse and reduced bolt weight compared to traditional straight blowback systems. Check out our CMMG Resources article & video to learn more about what sets Radial Delayed Blowback apart.
We aim to please, that’s why every CMMG product is backed by our Lifetime Quality Guarantee against material and workmanship defects. Learn More.