Cmmg Banshee Mk4 4.6X30 8 Armor Black

The CMMG Banshee Mk4 4.6x30 8" is a compact, lightweight AR-pattern pistol that pushes the boundaries of what a short-barreled personal defense carbine can do. Chambered in 4.6x30mm—a cartridge exclusive to CMMG and new to the U.S. civilian market—the Banshee Mk4 delivers controllable recoil and effective close-range performance in a package that weighs just 4.3 lbs and stretches only 23.7" overall. Built on CMMG's proven Mk4 platform with a forged 7075 aluminum lower and billet aluminum upper, this is a serious tool for shooters who want precision engineering, modularity, and proven reliability in an unconventional caliber.

The Banshee Mk4 is purpose-built around the 4.6x30mm cartridge with a dedicated gas system and a 1:5.9 twist barrel optimized for factory ammunition. The direct impingement operating system is tuned specifically to this cartridge, ensuring reliable cycling and minimal wear. The CMMG ZEROED linear compensator keeps muzzle flash and rise in check, while the micro gas port and proprietary FourSix gas block are engineered to handle the cartridge's unique pressure curve. At 8 inches of barrel, you get a platform that's nimble enough for close-quarters work yet balanced enough for precise fire at intermediate distances.

CMMG equipped this pistol with their complete parts suite: a drop-in single-stage trigger for clean breaks, an ambidextrous charging handle, and the RipBrace for stability and control. The EML7 M-LOK handguard gives you rail space for lights, lasers, or other accessories without excess bulk. Standard Cerakote finish protects the aluminum throughout, and you get a 40-round magazine that takes full advantage of the cartridge's compact dimensions. If you're drawn to AR ergonomics but want to venture beyond conventional calibers, the Banshee Mk4 is worth serious consideration.

Key Features

• 4.6x30mm caliber—first civilian AR-pattern rifle in this cartridge
• 8" barrel with 1:5.9 twist, optimized for 4.6x30mm ballistics
• Direct impingement with micro gas port and CMMG FourSix-specific gas block
• Forged 7075 aluminum lower and billet 6061 T6 aluminum upper receiver
• CMMG ZEROED linear compensator (1/2 x 28 threads)
• CMMG ZEROED drop-in single-stage trigger
• Ambidextrous charging handle and 60/90-degree safety selector
• EML7 M-LOK handguard for accessory mounting
• RipBrace for stability and control
• Includes 40-round magazine
• Weighs 4.3 lbs; overall length 23.7"
• Cerakote finish (Armor Black)

Specifications

Frequently Asked Questions

What ammunition does the CMMG Banshee Mk4 use?

The Banshee Mk4 fires 4.6x30mm ammunition. This is an exclusive CMMG cartridge and is new to the civilian U.S. market. The rifle is optimized for 4.6x30mm with a 1:5.9 twist barrel and a proprietary gas system tuned to this round's pressure curve.

How many rounds does the included magazine hold?

The CMMG 40-round magazine is included with the Banshee Mk4, giving you substantial capacity in a compact package suited to the 4.6x30mm cartridge.

Is the Banshee Mk4 a registered short-barreled rifle (SBR)?

The Banshee Mk4 is configured as an AR pistol with an 8" barrel and CMMG RipBrace. You are responsible for understanding and complying with all applicable federal, state, and local firearms laws regarding short-barreled firearms and braced pistols. Consult your local authorities or a qualified attorney if you have questions about your jurisdiction's regulations.

Can I add accessories to the Banshee Mk4?

Yes. The rifle features an EML7 M-LOK handguard that supports standard M-LOK accessories. The muzzle device has 1/2 x 28 threads for suppressors or other muzzle attachments, and the flat-top upper receiver accepts standard Picatinny-mounted optics.