CMMG 55BB40BMB Resolute MK4 5.56 NATO 16.1" Rifle

The CMMG 55BB40BMB Resolute MK4 5.56 NATO 16.1" rifle is a purpose-built platform engineered for operators who demand reliability without compromise. Designed for duty, training, and defensive applications, this rifle combines combat-proven ergonomics with modern manufacturing standards that meet professional law enforcement and military specifications. The Resolute MK4 platform represents CMMG's commitment to delivering field-ready performance at a professional-grade standard.

Built around the 5.56 NATO cartridge, the 16.1-inch barrel delivers optimal velocity and accuracy for intermediate-range engagements while maintaining a compact profile suitable for vehicle operations and tactical entries. The barrel length balances muzzle velocity with handling characteristics—critical for both speed and precision in high-stress scenarios. The rifle features a modern ergonomic design with integrated controls positioned for ambidextrous operation, allowing rapid magazine changes and immediate action drills regardless of shooting hand. This configuration supports the modular approach CMMG is known for, enabling field-proven reliability under the demanding conditions professional users expect.

Law enforcement tactical teams, military units, and serious civilian shooters benefit most from the Resolute MK4's design philosophy—function first, features second. The rifle accepts standard 5.56 NATO ammunition and AR-pattern accessories, ensuring compatibility with established supply chains and existing tactical equipment. Whether deployed for duty carry, training qualification, or home defense readiness, this rifle performs consistently across diverse ammunition types and environmental conditions. The 16.1-inch configuration provides the handling advantage needed for CQB while retaining sufficient sight radius and velocity for precision work beyond 100 meters.