The CMMG Banshee MK4 Upper Group (brand part number 22B5BD4AB) lets builders skip the compromise of a rimfire clone and instead run a genuine AR built on the Mk4 platform that just happens to be chambered in .22 LR. Built by CMMG with a 4.5-inch barrel, the shortest the company offers in any caliber, this traditional-blowback upper works with any standard AR15 lower group when paired with CMMG’s .22 AR Conversion Mags. It ships complete with a bolt carrier group and CMMG’s ZEROED accessories, including a polymer dust cover, an ambidextrous charging handle, and a flash hider, all finished in Cerakote.

Key Specifications

• Chambered in .22 LR on the Mk4 platform.
• Barrel length is 4.5 inches, the shortest CMMG offers in any caliber.
• Operating system is traditional blowback, suited to rimfire pressures.
• Twist rate is 1:16, matched to standard .22 LR bullet weights.
• Barrel material is 4140 chromoly steel with a salt bath nitride finish.
• Muzzle device is a CMMG ZEROED flash hider, threaded 1/2×28.
• Upper receiver is billet 6061-T6 aluminum.
• Handguard is the CMMG EML4 M-LOK free-float design.
• Includes a CMMG ZEROED ambidextrous charging handle and bolt carrier group.
• Overall length is approximately 12.8 inches, weighing 2.2 pounds.

Frequently Asked Questions

What magazines does this upper use? It is designed to run with CMMG’s .22 AR Conversion Mags on any standard AR15 or Mk4 lower.

What operating system does this upper use? Traditional blowback, suited to rimfire pressures.

Buy the CMMG Banshee MK4 .22 LR Upper Group

Build an ultra-compact rimfire AR with a genuine Mk4 upper group. Order this AR-15 upper from our Lubbock, Texas gun shop, and we will get it to your door as soon as it’s ready to ship.