CMMG Banshee 5.7x28mm 5" Complete Upper - Armor Black Cerakote

The CMMG Banshee complete upper receiver group brings the compact, fast-handling ergonomics of CMMG's Mk57 platform to your existing AR-platform lower. Chambered in 5.7x28mm, this upper is purpose-built around a flat-shooting cartridge with minimal recoil, making it an ideal foundation for a personal-defense pistol, truck gun, or compact short-barrel rifle build.

At the core of the upper is a 5" barrel backed by a 1:9" twist, well-suited for the full range of available 5.7x28mm projectiles. The receiver is CNC-machined from billet 6061-T6 aluminum and finished in Armor Black Cerakote for a durable, low-visibility surface. An M-LOK free-float handguard in matching Armor Black keeps the barrel fully floated for repeatable accuracy while providing ample accessory mounting space along the ventilated rail.

The Banshee upper is engineered around CMMG's Mk57 architecture and accepts standard FN Five-seveN-pattern 5.7x28mm magazines, giving builders a familiar AR-platform manual of arms with broad ammunition availability. Drop it onto a mil-spec lower, pair it with your preferred brace or stock, and you have a compact, hard-hitting PDW ready for the range or the field.