CMMG RESOLUTE MK4 Upper Group 6mm ARC 16.1

The CMMG Resolute MK4 Upper Group is a complete AR-15 pattern upper chambered for 6mm ARC and built for extended-range capability. This upper ships complete with bolt carrier group and ZEROED accessories, and is configured to interface with standard AR-15 lowers. The 16.1 inch barrel and precision components are intended to support accurate, consistent performance for precision and long-range shooting applications.

Key Specifications

• The caliber is 6mm ARC.
• The barrel length is 16.1 inches.
• The barrel twist rate is 1:7.5.
• The barrel material is 416SS SBN.
• The included muzzle device is a CMMG ZEROED Muzzle Brake.
• The muzzle thread pattern is 5/8 x 24.
• The gas port location is set for Rifle gas systems.
• The gas block is a 0.750 Non-Adjustable design.
• The upper receiver is made from Billet 6061 T6 Aluminum.
• The handguard is a CMMG EML15 M-LOK.

Built as a turnkey solution for shooters who want to bring 6mm ARC capability to an AR-15 lower, the Resolute MK4 upper balances durability and precision in a complete package. Its combination of a stainless barrel, robust billet receiver, and accessory-ready handguard makes it suitable for deliberate precision work and long-range courses of fire while remaining practical for repeatable, consistent use.