If you want the best an AR has to offer, then the 300 Series is your choice. This AR upper group is fitted with every desired feature including a black hard coat anodized finish that can be upgraded to your choice of 10 Premier Cerakote colors, a CMMG RML15 M-Lok handguard, CMMG ZEROED Ambi charging handle, and CMMG’s SV muzzle brake. Chambered in 5.7x28mm, this upper group is ready for your next AR build.
The Mk57 platform accepts FN FiveSeven-style 5.7×28 magazines, and features a unique magazine release. Mk4/mil-spec AR15 lower receivers can be used along with CMMG 5.7 conversion magazines.
All of our Upper Groups come complete with BCG.
All CMMG products come with our Lifetime Quality Guarantee.
|CALIBER||5.7X28MM, 5.7X28MM (CONVERSION)|
|OPERATING SYSTEM||RADIAL DELAYED BLOWBACK|
|BARREL MATERIAL||4140CM, SBN|
|MUZZLE DEVICE||COMPENSATOR SV BRAKE|
|MUZZLE THREAD||1/2 X 28|
|GAS PORT LOCATION||N/A|
|UPPER RECEIVER||FORGED 7075-T6 AL M4 TYPE UPPER|
|HAND GUARD||CMMG RML15 M-LOK|
|FINISH||HARD COAT ANODIZED RECEIVERS AND HAND GUARD (CAN BE UPGRADED TO CERAKOTE)|
|CHARGING HANDLE||CMMG ZEROED AMBI CHARGING HANDLE AR15|