CMMG BNSHE MK4 300BK 12.5″ PB 30R AB

Description

The CMMG Banshee MK4 in .300 AAC Blackout is built for shooters who want a compact, hard-use AR-pattern pistol that handles both supersonic and subsonic loads without fuss. The pistol-length gas system is deliberately matched to the 12.5-inch barrel: at that barrel length, a pistol-length port keeps dwell time appropriate for the cartridge’s pressure curve, which matters when you are running suppressed with heavy subsonic projectiles or cycling lighter supersonic defensive loads through the same gun. Getting that balance right is one of the less-discussed reasons the .300 Blackout format rewards careful gas system selection.

The barrel is machined from 4140 chrome moly steel and finished with a salt bath nitride treatment, which hardens the bore and exterior simultaneously and resists corrosion without the thickness penalty of a chrome lining. The 1:7 twist rate stabilizes the full range of .300 Blackout projectiles, including the heavier subsonic bullets that need a faster spin to stay stable at their reduced velocities. The upper receiver is billet 6061 T6 aluminum, while the lower is forged 7075 T6 — the difference in alloy reflects the different stress profiles each receiver sees in use. The handguard is the CMMG EML11 M-LOK, an eleven-inch format that gives enough real estate for a forward grip or light without pushing the overall length out unnecessarily.

The ZEROED suite of components — ambidextrous safety selector with selectable 60- or 90-degree throw, drop-in single-stage trigger, ambidextrous charging handle, and pistol grip — reflects a deliberate effort to make the controls consistent and accessible regardless of which hand is dominant. The CMMG Ripbrace receiver extension and the included Magpul 30-round PMAG round out a platform that ships ready to use. Sights are not included; the optics-ready upper leaves that choice entirely to the shooter.