Rise Armament Complete Upper 6mm ARC 18" – AR-15 Platform

The Rise Armament Complete Upper delivers 6mm ARC chambering on an AR-15 platform with an 18-inch barrel optimized for extended-range performance. This complete assembly arrives ready to mate with any mil-spec AR-15 lower receiver, offering shooters the ballistic advantages of 6mm ARC—flatter trajectories and superior wind resistance compared to 5.56 NATO—without building a new rifle from scratch.

Constructed with a forged upper receiver in a Burnt Bronze Cerakote finish, this unit includes a mid-length gas system, bolt carrier group, and charging handle for immediate installation. The 18-inch barrel length provides the velocity needed to maximize the 6mm ARC cartridge's long-range potential while maintaining overall handling balance. No gunsmithing required—install on your existing mil-spec lower and function-check before heading to the range.

• Caliber: 6mm ARC
• Type: Complete Upper Assembly
• Compatible Lower: Mil-Spec AR-15
• Barrel Length: 18 inches
• Material: Forged aluminum upper receiver
• Finish: Burnt Bronze Cerakote
• Includes: BCG, charging handle, handguard
• Installation: Attaches to any mil-spec AR-15 lower receiver