CMMG MK4 Upper Group .300 BLK – Dissent/Banshee

The CMMG MK4 Upper Group is a modular upper assembly designed for the .300 BLK AR platform. Source data shows this product exists in both DISSENT and BANSHEE configurations and ships with variant-specific components and accessories. These upper groups integrate CMMG components intended to simplify bufferless and traditional AR-style builds while supporting .300 BLK ammunition.

Key Specifications

• The manufacturer is CMMG.
• The platform designation is MK4.
• The cartridge is chambered for .300 BLK.
• The operating system is Direct Impingement.
• The barrel twist is 1:7.
• The barrel material is 4140CM SBN.
• The standard finish is Cerakote.
• The muzzle thread is 5/8 x 24.
• Charging-handle options are listed as side or ambidextrous depending on configuration.

These MK4 upper groups offer a flexible foundation for a variety of .300 BLK builds, with configuration-dependent choices for muzzle devices, handguards, and accessory fittings. Choose the configuration that matches your intended build profile and accessory requirements to get the specific balance of compactness, controls, and compatible components you need.