CMMG BNSHE MK4 5.7X28 5″ PB 32RD AB

Description

The CMMG Banshee Mk4 in 5.7x28mm is built for shooters who want a compact, high-capacity pistol-format AR that feeds a round originally developed for personal defense and armor-defeating applications. The 5.7x28mm cartridge is inherently flat-shooting and produces modest recoil for its velocity, which pairs naturally with a short host like the Banshee platform — keeping the package maneuverable without fighting the shooter on every shot.

The 5-inch barrel gives up some velocity compared to longer tubes, but the 5.7x28mm was engineered around short barrels to begin with, so the trade-off is less punishing here than it would be with a cartridge optimized for longer sight radii. The 32-round magazine means fewer reloads in any high-round-count session, which matters in a platform this size where magazine changes require deliberate technique.

The ambidextrous safety is a functional choice, not a cosmetic one — a pistol this compact tends to get used in awkward positions where a right-hand-only control becomes a real limitation. The optics-ready configuration means no fixed sights are eating up rail space or forcing a removal before you can mount a reflex sight at the correct height. CMMG’s Armor Black finish is applied to the lower receiver and complements the Mk4 upper. The Banshee line is built around CMMG’s MkGs-pattern lower, which uses a dedicated bolt and feed system rather than forcing a 5.7x28mm round through geometry designed for another cartridge.