CMMG AR-15 Resolute 300 Mk57 Radial Delayed Blowback Upper Receiver Assembly 5.7x28mm 16″ Barrel M-LOK Handguard


Category: Product ID: 13230


CMMG’s Resolute is engineered with purpose for those who refuse to compromise on quality. The Resolute features a medium tapered barrel designed for balance, accuracy and maneuverability. The Resolute offers a billet 6061 T6 Aluminum upper receiver assembly with a bolt carrier group, and a Cerakoted receiver and handguard. Whether it’s hunting, personal defense, or target shooting, this RESOLUTE Upper Group is just the thing to finish your next carbine build. Combine this RESOLUTE Upper Group with either the 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!



  • ZEROED AR15 Polymer Dust Cover
  • ZEROED AR15 Ambi Charging Handle
  • ZEROED Muzzle Brake

Made In United States of America


Product Information

Cartridge 5.7x28mm FN
Color Armor Black
Finish Cerakote
Material Aluminum
Extra Features Radial Delayed Blowback
Weight 4 Pound
Barrel Length 16.1 Inches
Twist 1:9 Inches
Threads 1/2″-28
Barrel Contour Medium
Barrel Finish Black Salt Bath Nitride
Chrome Lined No
Upper Receiver Type A3 Flat-Top
Barrel Material 4140 Chrome Moly Steel
Handguard CMMG EML15 M-LOK
Bolt Carrier Assembly Included Yes
Country of Origin United States of America
Compatible With

Delivery Information

Shipping Weight 4.680 Pounds


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