CMMG 55BB40BAB Resolute MK4 5.56 NATO 16.1" Rifle

The CMMG 55BB40BAB Resolute MK4 5.56 NATO 16.1" rifle is purpose-built for operators who demand a compact, reliable platform capable of delivering precision fire in confined spaces and tactical environments. Whether deployed for home defense, professional security work, or tactical training, this mid-length rifle balances maneuverability with effective range. The 16.1-inch barrel strikes the optimal compromise between velocity retention and handling agility—a proven configuration across law enforcement and military applications where door-breaching, vehicle operations, and close-quarters drills demand a weapon that doesn't sacrifice accuracy for compactness.

Built on CMMG's proven Resolute platform, the MK4 incorporates precision engineering that minimizes point-of-impact shift and maximizes reliability under sustained fire. The 5.56 NATO chambering delivers proven ballistic performance with widespread ammunition availability and compatibility across military and civilian inventories. At 0.52 lbs, the rifle's lightweight construction reduces shooter fatigue during extended operations while maintaining structural rigidity critical for maintaining zero. The 31.3-inch overall length (with standard stock) provides the compact footprint essential for vehicle mounting, building clearance, and rapid deployment in high-density environments without sacrificing sight radius or accessory rail real estate.

This rifle is ideal for tactical professionals, law enforcement agencies, and serious civilians seeking a proven AR-platform system that excels in sub-100-yard engagements while remaining effective to 300+ yards. The MK4's modular design accepts standard AR-15 components, allowing customization of triggers, grips, optic mounts, and furniture to match mission-specific requirements. The 16.1-inch barrel works seamlessly with sound suppressors and flash hiders (via standard mil-spec threading), making it equally suited for suppressed operations where backpressure and reliability are non-negotiable. Field-proven reliability, repeatable accuracy, and the ability to function flawlessly across temperature extremes and adverse conditions make the CMMG Resolute MK4 a smart investment for operators who understand that equipment durability directly impacts mission success.