CMMG Upper Group Banshee 5.7x28mm 8" Black

The CMMG Upper Group Banshee 5.7x28mm 8" Black is a precision-engineered upper assembly designed for shooters building a compact personal defense weapon (PDW) platform around the AR15 architecture. The 5.7x28mm cartridge delivers superior ballistics compared to traditional pistol calibers while generating significantly less felt recoil—a critical advantage in dynamic tactical environments where follow-up shot accuracy and shooter control directly impact engagement outcomes.

This 8-inch barrel assembly weighs 3.3 pounds and is compatible with CMMG Mk57 lowers or standard AR15/Mk4 lowers when paired with CMMG 5.7 AR conversion magazines. The black finish provides a professional, low-profile appearance suitable for duty or home defense setups. As a complete upper group, this assembly arrives ready to mate with your chosen lower receiver, streamlining the build process while maintaining the modular advantages inherent to AR-platform weapons systems.

Law enforcement, military personnel, and civilian shooters focused on non-lethal or reduced-penetration duty applications have increasingly adopted the 5.7x28mm for its ballistic profile—delivering energy transfer comparable to duty pistol rounds while minimizing over-penetration risk in sensitive environments. The compact 8-inch barrel configuration maintains velocity while keeping overall weapon length manageable for vehicle storage, close-quarters work, and specialized detail operations. This upper group is ideal for operators seeking a modular, purpose-built PDW without purchasing a complete firearm platform.