The CMMG Banshee MK4 is a pistol-caliber firearm chambered in 9mm with a 5-inch barrel and Arm Black finish. It ships with a 30-round magazine. 
 

Key Specifications 

• Brand: CMMG 
• Model: Banshee MK4 
• Caliber: 9mm 
• Action: Semi Auto 
• Capacity: 30+1 
• Barrel Length: 5" 
• Color: Arm Black 
   

Detailed Features 

• CMMG MK4 platform chambered in 9mm 
• 5-inch barrel 
• 30-round magazine included 
• Arm Black finish

CMMG Banshee MK4 owners in 9mm typically cite the radial delayed-blowback operating system as the defining characteristic that separates it from straight-blowback pistol-caliber platforms. Recoil is described as noticeably softer, which owners find useful for faster follow-up shots at the range.

The 5-inch barrel gives the Banshee MK4 a compact profile, and those running it in a braced or stocked configuration appreciate the maneuverability. Some note the 5-inch barrel produces more muzzle flash with standard 9mm loads than longer configurations in the same line, which comes up in indoor range settings.

The Banshee's price relative to other pistol-caliber platforms is the most common discussion point. Buyers who prioritize the CMMG operating system find the premium reasonable. Those comparing on capacity and caliber alone sometimes find it harder to justify against less expensive alternatives, and that divide tends to run along how much the buyer values the reduced felt recoil.