CMMG BANSHEE MK4 Upper | 4.6x30mm | 8 BLK

The CMMG Banshee MK4 Upper Group adapts the AR-15 platform to the 4.6x30mm chambering while maintaining compact dimensions and low felt recoil. This upper group ships complete with a bolt carrier group and ZEROED accessories and is designed to pair with any standard AR-15 lower and CMMG 4.6x30mm magazines. Its compact configuration suits PDW-style builds and short-range practical or competition shooting where maneuverability and quick handling are priorities.

Product Specifications

• This upper group ships complete with a bolt carrier group and ZEROED accessories including a polymer dust cover, ambidextrous charging handle, and linear compensator.
• The platform is listed as Mk4.
• The caliber is 4.6x30mm.
• The operating system is Direct Impingement.
• The barrel length is listed as 8.
• The barrel twist rate is 1:5.9.
• The barrel material is specified as 4140CM SBN.
• The muzzle device is a CMMG ZEROED Linear Compensator.
• The muzzle thread is 1/2 x 28.
• The gas port location is noted as Micro.
• The gas block is FourSix Specific .750.
• The upper receiver is made from Billet 6061 T6 Aluminum.
• The hand guard is a CMMG EML7 M-LOK.
• The finish is listed as Cerakote Standard.
• The UPC is 810097503755.

Compact and purpose-built, this upper group is appropriate for shooters assembling a compact PDW-style AR variant or for use in short-range practical shooting and training. Its billet receiver, dedicated FourSix gas components, and included ZEROED accessories make it a straightforward way to build a complete, ready-to-configure upper while keeping weight and overall length low.