The CMMG RESOLUTE Mk4 .300 Blackout Upper Group, 16.1-Inch, No BCG or Charging Handle (CMMG part no. 30BC40A-AB) is assembled minus the bolt carrier group and charging handle. CMMG offers it for builders who already have their own bolt and handle or want to choose them. The 16.1-inch barrel has a 1:7 twist and a CMMG A2 flash hider threaded 5/8×24. A billet receiver and a CMMG EML15 M-LOK handguard come installed.

Key Specifications

• The chambering is .300 BLK, the .300 Blackout cartridge.
• The barrel length is 16.1 inches with a 1:7 twist and a medium taper contour.
• The barrel is 4140 chrome moly with CMMG’s SBN finish.
• The muzzle device is a CMMG A2 flash hider, threaded 5/8×24.
• The operating system is direct impingement with a carbine gas port.
• The gas block is an adjustable 0.750-inch model for tuning the gas flow.
• The upper receiver is billet 6061 T6 aluminum, a light and rigid alloy.
• The handguard is a CMMG EML15 M-LOK, which accepts M-LOK accessories.
• The charging handle is not included, nor is a bolt carrier group.
• The upper weighs 3.4 pounds and measures 25 inches long, with a Cerakote finish.

Frequently Asked Questions

Does this upper include a bolt carrier group or charging handle? No. CMMG sells this version assembled minus the BCG and charging handle, so you supply both.

What muzzle device does it have? It has a CMMG A2 flash hider threaded 5/8×24.

What platform is it? CMMG lists the Mk4 platform, with a 16.1-inch barrel in .300 BLK.

Buy the CMMG RESOLUTE Mk4 .300 Blackout Upper Group, 16.1-Inch, No BCG or Charging Handle

Supply your own bolt and handle and you have a .300 Blackout carbine upper. Browse more AR-15 uppers from CMMG. Order from our Lubbock, Texas gun shop for fast, direct shipping.