CMMG Banshee MK4 | 54A3B0FMB | 5.7x28mm | 5-inch | 40+1

The CMMG Banshee MK4 (54A3B0FMB) is an ultra-compact AR-platform pistol chambered in 5.7x28mm with a 5-inch barrel and a high-capacity magazine option. Its compact footprint and threaded, Black Nitride medium-taper barrel make it suitable where a short-barrel AR configuration is required. For optics, a compact 1x red dot such as the Trijicon MRO pairs well with the Banshee for fast target acquisition while preserving sight radius. Typical applications include range training and action-style competition where compact handling and controllable recoil are priorities.

Product Specifications

• The model is CMMG Banshee MK4 (54A3B0FMB).
• The caliber is 5.7 x 28 mm.
• The action is Semi-Auto.
• The capacity is 40 + 1.
• The barrel measures 5 inches and features a Black Nitride medium taper threaded finish.
• The handguard is the EML4 M-LOK with slots at 3, 6, and 9 o’clock and an integrated handstop.
• The receiver includes a full-length Picatinny top rail for optics and accessories.
• The handguards use Midnight Bronze Cerakote aluminum finishes as specified in the product name.
• The grips are CMMG Zeroed.
• The safety is an Ambidextrous Safety Lever.
• The listed weight is 4.80 lbs.
• The listed weight range is 4 lbs to 4.99 lbs.
• The barrel length range is 5 inches to 5.99 inches.
• The item UPC is 810148624194.

Compact, well-appointed, and purpose-built for controlled handling, the Banshee MK4 delivers a balance of maneuverability and capacity in a modern AR pistol package. Its combination of a threaded Black Nitride barrel, M-LOK handguard, and full-length Picatinny rail provides a flexible platform for optics and accessories tailored to range and competition use. If you want a compact AR-style pistol that emphasizes controllability and modularity, this configuration is a practical choice.

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