CMMG Resolute MK4 Upper Group .300 BLK 16.1

Originally developed with subsonic and suppressed applications in mind, the CMMG Resolute MK4 Upper Group in .300 BLK combines a modern AR platform with features intended for a wide range of loadings. This upper group is built to work with any standard AR-15 lower and ships with CMMG ZEROED accessories and a bolt carrier group. It is presented in a Cerakote finish and uses a direct impingement operating system.

Key Specifications

• The platform is Mk4.
• The caliber is .300 BLK.
• The operating system is Direct Impingement.
• The barrel measures 16.1.
• The barrel twist rate is 1:7.
• The barrel material is 4140CM SBN.
• The muzzle device is a CMMG ZEROED Muzzle Brake with 5/8 x 24 threads.
• The gas port location is Carbine with a 0.750 Non-Adjustable gas block.
• The upper receiver is Billet 6061 T6 Aluminum and the hand guard is CMMG EML15 M-LOK.
• This upper group ships complete with a bolt carrier group and CMMG ZEROED accessories including an ambi charging handle and polymer dust cover.

The Resolute MK4 upper group delivers a complete, ready-to-install option for builders seeking a .300 BLK configuration that supports both suppressed and unsuppressed use-cases. With a billet receiver, M-LOK hand guard, and CMMG ZEROED hardware included, this upper provides a precise, component-level foundation for a variety of carbine builds.