Steve L
I put it on my AR15 lower fits perfect. The color really looks good on my AR. THE WORKMANSHIP IS FANTASTIC
Forrest L.
Personal Defense Weapon (PDW)
Pistol Caliber Carbine (PCC)
Designated Marksman Rifle (DMR)
Short Barreled Rifle (SBR)
Expected to ship within 15-30 business days.
State/local restrictions may apply. Please review our Firearms Shipping Policy prior to ordering.
Personal defense calibers like 5.7x28mm have become a big thing in the last few years, and if you’re looking for PDW ballistics and the classic style and balance of a carbine then you’re in luck. Combine this RESOLUTE® Upper Group with either our Mk57 Lower or a standard AR15 lower group and CMMG®’s 5.7 AR Conversion Magazines and you’ll be ready to hit the range! 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
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.
Steve L
I put it on my AR15 lower fits perfect. The color really looks good on my AR. THE WORKMANSHIP IS FANTASTIC
Forrest L.
Excellent Fit and Finish
Top quality product from CMMG. Paired with a Bushmaster lower, fit was spot on and finish even matched, too. Very pleased as it performs flawlessly with a smooth action and magazine holds bolt open on last round. Shooting tight groups with FN 40 gr V-Max ammo. Appreciate the ambi charging handle and the light weight of the unit. 100% happy with the purchase. This will relegate the old .22 Mag to a dust collector.
Tom S.
Great Product
Functioned perfectly. Manual of arms the same as original upper. Holds bolt open on last round, appreciated! Close bolt using the same button as original. Finish and fitment are both top notch. Recommend without reservations.
William P.
Platform | Mk4, Mk57 |
Caliber | 5.7x28mm |
Operating System | Radial Delayed Blowback |
Barrel Length | 16.1 |
Barrel Twist | 1:9 |
Barrel Contour | MT |
Barrel Material | 4140CM, SBN |
Barrel Twist | 1:9 |
Muzzle Device | CMMG ZEROED Muzzle Brake |
Muzzle Thread | 1/2 x 28 |
Gas Port Location | N/A |
Gas Block | N/A |
Upper Receiver | Billet 6061 T6 Aluminum |
Hand Guard | CMMG EML15 M-LOK |
Finish | Cerakote Standard |
Charging Handle | CMMG ZEROED Ambi |
Weight | 4.0 lbs |
Length | 25.3" |
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Ordering prohibited items will result in order cancelation and a 15% restocking fee.