Description
MPN: 57B88BD-AB
FEATURES:
- Radial Delayed Blowback System - softer recoil impulse and reduced bolt weight
- Caliber: 5.7x28mm
- Finish: Armor Black Cerakote
- Upper Receiver: CMMG Mk4 Upper Receiver - 6061-T6 Aluminum
- Handguard: 4-Inch CMMG EML4 M-LOK Handguard
- Muzzle Device: CMMG ZEROED Linear Compensator
- Barrel: 8" 1:9 Salt Bath Nitrided 4140 Chrome Moly Steel
- Muzzle Thread Pattern: 1/2-28
- Bolt Carrier Group: CMMG Mk57 5.7x28mm Bolt Carrier Group
- Charging Handle: CMMG ZEROED AR15 Ambi Charging Handle
- HP and MPI Tested
*This upper receiver assembly has a barrel that is shorter than 16". This upper is only for use on AR pistol lower receivers and NFA-registered Short-Barreled Rifle (SBR) lower receivers. All NFA laws apply!
SPECIFICATIONS:
- Weight: ~2.9 lbs.
- Length: ~16.5"
COMPATIBILITY:
- CMMG Mk57 lower receivers
- CMMG Mk4 or standard AR-15 lower receivers when used with 5.7 AR Conversion Mags
- FN® Five-seveN® pattern magazines
INCLUDES:
- 1x CMMG Banshee 5.7x28mm 8" Complete Upper
- 1x CMMG Mk57 5.7x28mm Bolt Carrier Group
- 1x CMMG ZEROED AR15 Ambi Charging Handle
DETAILS:
Smooth-Shooting 5.7x28mm Performance
The CMMG Banshee 5.7x28mm Upper Group offers smooth shooting with low recoil, making it a practical option for users seeking faster target reacquisition. The 5.7x28mm chambering combines manageable handling with capable performance for recreational shooting, competition, and personal-defense setups. This CMMG Banshee 5.7 upper arrives as a complete assembly with the bolt carrier group and charging handle included.
Radial Delayed Blowback for Better Control
Designed with CMMG’s Radial Delayed Blowback System, this CMMG 5.7x28 upper helps reduce felt recoil while maintaining lightweight handling. The system delays and controls the bolt’s rearward movement, allowing CMMG to use less bolt mass than a traditional straight-blowback design. The included Mk57 bolt carrier group is matched to the operating system to support dependable cycling.
Versatile Fit for AR Platforms
This 5.7mm AR upper group is compatible with CMMG Mk57 lowers and standard AR-15 lowers when used with the appropriate 5.7 AR conversion magazines. It also works with FN Five-seveN pattern magazines when paired with the compatible lower configuration. The 8-inch barrel gives the 5.7 upper a compact profile while providing more barrel length than shorter Banshee configurations.
Premium Components and Finish
The upper features an Armor Black Cerakote finish, a 6061-T6 aluminum CMMG Mk4 receiver, and a 4-inch CMMG EML4 M-LOK handguard. Its salt-bath-nitrided 4140 chrome-moly steel barrel uses a 1:9 twist rate and 1/2-28 muzzle threads. A CMMG ZEROED Linear Compensator directs muzzle blast forward, while the ambidextrous charging handle supports operation from either side.
Ready for Your Next Upgrade
Whether you’re starting a new build or updating an existing setup, the CMMG 5.7x28 upper combines the receiver, barrel, handguard, muzzle device, bolt carrier group, and charging handle into a single package. That complete configuration reduces the number of individual operating components you need to source separately.
Wing Tactical also carries additional upper receiver parts, bolt carrier groups, and muzzle devices for AR-platform builds. Before ordering this 5.7 upper, confirm that your lower receiver and magazine setup match the compatibility requirements above.
