CMMG BANSHEE MK4 5.56 NATO 12.5" Tungsten upper receiver Carbine

The CMMG BANSHEE MK4 5.56 NATO 12.5" Tungsten upper receiver carbine delivers compact, modular firepower designed for operators who demand precision in confined spaces. Purpose-built for law enforcement, military, and civilian tactical users, this upper receiver assembly excels in vehicle operations, building clearances, and close-quarters scenarios where full-length carbines become liabilities. The 12.5-inch barrel strikes the critical balance between velocity retention and maneuverability, making it ideal for duty rifles, patrol carbines, and dedicated home-defense platforms that prioritize speed and accuracy over extended-range engagement.

CMMG's Tungsten upper receiver construction provides superior durability and recoil mitigation compared to standard aluminum designs. The 5.56 NATO chamber accepts both commercial .223 Remington and military-spec 5.56×45mm ammunition, offering flexibility in loadout options and supply chains. At 7.95 lbs, this upper assembly maintains a lightweight profile while the precision-machined receiver ensures consistent zero retention and reliable function across thousands of rounds. The 12.5-inch barrel length generates approximately 2,700–2,850 fps with standard 55-grain loads, delivering effective terminal performance while maintaining subsonic compatibility with suppressed configurations—a critical feature for tactical operations requiring noise discipline.

This upper receiver integrates seamlessly with any mil-spec AR-15 lower receiver, including CMMG's proprietary systems and standard civilian or law-enforcement platforms. The modular design allows rapid reconfiguration with different handguards, optics mounts, and muzzle devices—essential for operators rotating between multiple mission profiles. Installation requires only standard AR assembly knowledge: torque the barrel extension, stake the gas tube roll pin, and secure to your lower receiver with proper bolt carrier assembly. Ideal for rifle teams, special operations personnel, and serious enthusiasts seeking a compact upper that does not compromise ballistic performance or ergonomic reliability.