CMMG BANSHEE MK57 chambered in 5.7x28mm with an 8″ nitride medium-taper threaded barrel, EML-7 M-LOK handguard, 20+1 capacity and CMMG RipBrace. Accepts FN Five-seveN pattern magazines.
The CMMG BANSHEE MK57 is a compact AR-style pistol chambered in 5.7x28mm with an 8″ medium-taper, black nitride threaded barrel and radial delayed blowback operation. Built on the MK57 platform, it accepts FN Five-seveN pattern magazines and ships with a 20rd ProMag magazine for a 20+1 capacity. For optics, a low-power variable optic such as the Vortex Strike Eagle 1-6×24 pairs well for close-to-mid-range work while keeping weight and footprint appropriate for an AR pistol.
This configuration suits precision-oriented range training and competition-style target work where the 5.7x28mm cartridge’s flat trajectory and reduced felt recoil can be leveraged. The platform keeps AR ergonomics intact while providing the compact handling expected from an AR pistol.
Product Specifications
The manufacturer is CMMG.
The model is BANSHEE MK57.
The manufacturer part number is 57A340FAB.
The caliber is 5.7 x 28 mm.
The action is Semi-Auto.
The barrel measures 8″ with a medium taper and is nitride treated.
The barrel twist rate is 1:9.
The operating system is Radial Delayed Blowback.
The muzzle device is a CMMG ZEROED Linear Compensator with a 1/2 x 28 muzzle thread.
The upper receiver is Billet 6061 T6 Aluminum.
The lower receiver is Mk57 Forged 7075 T6 Aluminum.
The handguard is a CMMG EML7 M-LOK with full-length M-LOK slots.
The trigger is a ZEROED Drop-In Single Stage.
The included magazine is a 20rd ProMag (accepts FN Five-seveN pattern magazines).
The UPC is 810148624378.
The BANSHEE MK57 combines a compact form factor with AR-style controls and a purpose-built MK57 receiver set. Its EML-7 M-LOK handguard and full ZEROED parts kit deliver an immediately usable platform for range-focused shooters and competition entrants who prioritize controllability and modularity in a short-barrel package. The included RipBrace and ambidextrous controls keep the interface familiar while the radial delayed blowback system manages the cartridge’s characteristics cleanly.
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