CMMG Mk4 Banshee .300 AAC Blackout AR-15 Pistol, 8 in Threaded Barrel, Matte Gray, Ambi Controls, M-LOK Handguard, 2x 20rd Mags
This CMMG Mk4 Banshee AR-15 pattern pistol in .300 AAC Blackout stands out with its 8-inch threaded barrel, slick-side upper with bolt-on brass deflector, and a free-float M-LOK handguard. It features ambidextrous controls, CMMG's Fastback telescoping brace, and a uniform matte gray finish over premium aluminum receivers. It comes with two 20-round PMAGs marked specifically for 300 BLK.
Condition
Overall Condition: Good condition, showing some signs of prior use and handling.
Bore Condition: Excellent - Clean, mirror finish, no signs of wear.
Bore Rifling: Excellent Rifling - Sharp lands and grooves.
Specific Condition Notes: Some markings from prior handling and use are present. Refer to the photos for close-ups.
What’s Included
- CMMG Mk4 Banshee .300 AAC Blackout AR pistol
- Two 20-round Magpul PMAG AR 300 B GEN M3 polymer magazines marked "300 BLK"
The Mk4 Banshee is built on the AR-15 platform and chambered in .300 AAC Blackout (7.62x35mm), using a direct impingement operating system. Its 8-inch barrel is threaded and fitted with a pronged/crowned device, offering a compact profile suited to the caliber.
The flat-top slick-side upper deletes the forward assist and pairs with a bolt-on brass deflector and an ejection-port cover. An aluminum free-float M-LOK handguard with interrupted 12 o'clock Picatinny sections provides mounting flexibility while keeping the front end streamlined.
Controls are ambidextrous, including the charging handle and safety selector, with selector markings labeled SAFE/SEMI. The pistol wears CMMG's Fastback telescoping brace (U.S. Patent 10,551,144) labeled FASTBACK and a CMMG-branded polymer grip with aggressive texturing.
Construction details include a billet 6061-T6 aluminum upper receiver and a forged 7075-T6 aluminum lower. The receivers and handguard share a uniform matte gray finish contrasted by black small parts. Made in the USA.
Capacity is listed at 20+1 with the included magazines. Two Magpul PMAG AR 300 B GEN M3 20-round polymer magazines, clearly marked "300 BLK," are included.