The CMMG Banshee 5.7x28mm 8in Upper Group, Black (CMMG part no. 57B88BDAB) builds a personal defense weapon around the 5.7x28mm cartridge, which delivers superior ballistics and less felt recoil than most pistol-caliber PDWs. The 8-inch Banshee upper group lets a builder assemble the PDW AR15 of their choice, running on CMMG’s Radial Delayed Blowback operating system for reliable cycling in a compact package. It’s compatible with either a CMMG Mk57 lower or a standard AR15/Mk4 lower when paired with CMMG 5.7 AR Conversion Magazines, sold separately. Every upper group ships complete with a bolt carrier group and CMMG’s ZEROED accessories, including a ZEROED Polymer Dust Cover, ZEROED Ambi Charging Handle, and ZEROED linear compensator, and it’s backed by CMMG’s Lifetime Quality Guarantee. Builders who want a complete, ready-to-run 5.7x28mm upper get everything needed except the lower in one box.

Key Specifications

• Chambered in 5.7x28mm for reduced recoil compared to most PCC PDWs.
• 8-inch barrel length in the Banshee upper group configuration.
• Runs on CMMG’s Radial Delayed Blowback operating system.
• Compatible with a CMMG Mk57 lower or a standard AR15/Mk4 lower with CMMG 5.7 AR Conversion Magazines.
• Ships complete with a bolt carrier group installed.
• Includes a ZEROED Polymer Dust Cover and ZEROED Ambi Charging Handle.
• Includes a ZEROED linear compensator.
• Backed by CMMG’s Lifetime Quality Guarantee.
• Finished in black Cerakote.

Frequently Asked Questions

Does this upper come with a bolt carrier group? Yes, it ships complete with the BCG and CMMG’s ZEROED accessories installed.

What lower receivers is this compatible with? It works with a CMMG Mk57 lower or a standard AR15/Mk4 lower when used with CMMG 5.7 AR Conversion Magazines, sold separately.

Buy the CMMG Banshee 5.7x28mm 8in Upper Group, Black

Order this upper group from our Lubbock, Texas gun shop for fast, insured shipping, and browse the rest of our AR15 uppers selection to complete your build.