Cmmg Uppr Reso 200 Mk4 16.1" 6mm Arc

The CMMG Upper Receiver 200 Mk4 16.1" in 6mm ARC is a purpose-built rifle upper designed for shooters seeking precision at extended range with reduced recoil and wind drift compared to 5.56mm NATO. This upper receiver chambered in 6mm ARC delivers ballistic efficiency through a modern intermediate cartridge that has gained traction among precision rifle competitors, hunters, and operators evaluating alternatives to established service calibers.

The 16.1-inch barrel on this Mk4 upper balances velocity and handling characteristics for 6mm ARC, maintaining supersonic performance at extended distances while keeping the overall package maneuverable in tactical or field environments. The upper receiver integrates with standard AR-pattern lower receivers, allowing builders to leverage existing components and familiarity with the AR platform. The CMMG 200 series designation indicates this is part of CMMG's precision-focused line, engineered for accuracy-critical applications where shooter capability and ammunition performance are matched for repeatable results.

This upper is suited for precision rifle training, distance marksmanship development, hunting medium game, and shooters building a dedicated 6mm ARC platform. The 6mm ARC cartridge has become standard in precision rifle competition and is gaining adoption among those seeking a high-efficiency, low-recoil alternative in a modern rifle format. Builders and shooters evaluating 6mm ARC uppers will find this Mk4 addresses the demand for purpose-built ARs optimized around this emerging cartridge rather than retrofitted designs.