CMMG Banshee Upper Group | 5.7x28mm | 8″

This CMMG Banshee upper group is a factory-complete 5.7x28mm AR-style upper built around an 8″ barrel and configured for compact PDW-style builds. It ships with a bolt carrier group and ZEROED-branded accessories and is compatible with CMMG Mk57 lowers or a standard AR15/Mk4 lower when used with CMMG 5.7 conversion magazines. The assembly uses a radial delayed blowback operating system and a lightweight billet upper for compact handling.

Ideal applications include short-range precision and competition or PDW-format range use where compact handling and low felt recoil are priorities. This upper is also suitable for builders assembling a dedicated 5.7x28mm AR-platform upper for recreational target work.

Product Specifications

• The caliber is 5.7x28mm.
• The platform is listed as Mk4 / Mk57.
• The operating system is Radial Delayed Blowback.
• The barrel length is 8 inches.
• The barrel twist is 1:9.
• The barrel contour is MT.
• The barrel material is 4140CM SBN.
• The muzzle device is a CMMG ZEROED Linear Compensator.
• The muzzle thread is 1/2 x 28.
• The upper receiver is Billet 6061 T6 Aluminum.
• The hand guard is a CMMG EML7 M-LOK.
• The finish is Cerakote Standard.
• The charging handle is a CMMG ZEROED Ambi.
• The package includes a bolt carrier group and ZEROED accessories (dust cover, ambi charging handle, linear compensator).
• The overall length is listed as 16.5 inches.
• The UPC is 810097504387.

The Banshee upper group offers a compact, purpose-built option for builders seeking a factory-complete 5.7x28mm upper. Its combination of a short MT-contour barrel, billet receiver, and M-LOK handguard provides a balance of maneuverability and modularity for PDW-style or short-range precision applications. The included ZEROED components simplify initial setup and make this upper a ready foundation for a dedicated 5.7x28mm AR-platform build.