The CMMG Banshee Mk4 AR-15 Upper Group in .338 ARC with a 10.5 inch barrel and Black finish (brand part no. 34B8D0F-AB) brings large-bore performance to the standard AR-15 platform. CMMG designed .338 ARC to emulate the sub- or supersonic versatility of the now-common .300 BLK cartridge while delivering more energy on target and requiring less gas-system tuning when switching between suppressed and unsuppressed shooting. As a complete upper group, it drops onto a compatible AR-15 lower to add serious close-range stopping power without building a whole new rifle.

Key Specifications

• Chambered in .338 ARC, built for sub- or supersonic loads with less gas-tuning hassle than comparable big-bore cartridges.
• Features a 10.5 inch barrel for a compact, maneuverable overall length.
• Finished in black to match standard AR-15 builds.
• Sold as a complete upper group, simplifying the swap onto a compatible AR-15 lower.

Frequently Asked Questions

Will this upper work with my current AR-15 lower? Yes, as a Mil-Spec AR-15 upper group it mates with a standard AR-15 lower receiver; just confirm your lower’s buffer and receiver extension are compatible with .338 ARC’s pressure curve per CMMG’s guidance.

Does .338 ARC work suppressed and unsuppressed without changing parts? CMMG designed .338 ARC specifically to minimize gas-system tuning between suppressed and unsuppressed shooting, unlike many other big-bore AR cartridges.

Buy the CMMG Banshee Mk4 .338 ARC Upper

Add big-bore performance to your AR-15 with a CMMG Banshee Mk4 upper from our AR15 uppers lineup. Order it from our Lubbock, Texas gun shop for fast, direct shipping.