The CMMG Banshee Mk4 is a semi-automatic AR pistol chambered in 5.56 NATO with a 12.5-inch direct-impingement barrel and a 1:7 twist rate. It is built on a CMMG 6-position fastback extension with CMMG Zeroed controls and a RipBrace, and it ships with a threaded 1/2x28 muzzle fitted with CMMG's Zeroed Linear Comp. The pistol feeds from a 30-round Magpul PMAG and keeps the platform light for fast handling. 
 

Key Specifications 

• Brand: CMMG 
• Model: Banshee Mk4 
• Caliber: 5.56 NATO 
• Action: Semi Auto 
• Capacity: 30 Rounds 
• Barrel Length: 12.5 inches 
• Finish: Midnight Bronze 
• Twist Rate: 1:7 
   

Detailed Features 

• 1/2x28 threaded muzzle fitted with CMMG's Zeroed Linear Comp 
• M-LOK handguard for accessory mounting 
• CMMG RipBrace pistol-brace configuration on a 6-position fastback extension 
• Includes a 30-round Magpul PMAG 
• No sights included, leaving the top rail open for an optic

Owners of the CMMG Banshee Mk4 tend to praise the direct-impingement action for reliable cycling across a range of 5.56 loads, and CMMG's fit and finish gets consistent marks for the price point. A subset of shooters mention checking screw torque after the first range trips, but most describe the platform as low-maintenance once broken in.

As an AR pistol, the Banshee Mk4 is compact and light enough for one-handed maneuvering in a truck or a home-defense role, and the RipBrace makes shouldering it comfortable for extended range sessions. Recoil impulse is mild for the chambering, though some owners add a lighter buffer or a different muzzle device to tune it further.

The Banshee lineup benefits from wide AR-pattern aftermarket compatibility, so owners swap handguards, grips, and optics without much fuss. Buyers generally see the Mk4 as good value against comparable AR pistols, with the bundled brace and comp adding to the perceived package price.