One Horse AR-15 Complete Upper – 18″ 6mm ARC

Elevate your precision shooting setup with the One Horse AR-15 Complete Upper in 6mm ARC, featuring an 18-inch barrel optimized for long-range accuracy and flat trajectories. The 6mm Advanced Rifle Cartridge (ARC) was purpose-built for the AR-15 platform, delivering exceptional ballistic performance in a lightweight, versatile package — ideal for hunters, competitive shooters, and serious enthusiasts who demand more from their rifle.

This complete upper assembly is ready to drop onto any standard mil-spec AR-15 lower receiver, making it an outstanding upgrade or build option without the hassle of sourcing and assembling individual components. The 18-inch barrel length maximizes the velocity potential of the 6mm ARC cartridge, providing a compelling balance of power, range, and maneuverability.

Whether you’re building a dedicated hunting rifle, stretching your range performance in competition, or simply upgrading your current AR-15 setup, this One Horse complete upper delivers reliable quality at a competitive price point.

Order online at Deep Roots Rifle Co and enjoy fast shipping straight to your door, or stop by our gun store in Eustis, Florida, where our knowledgeable staff is ready to help you find the right upper, complete your build, or answer any questions. At Deep Roots Rifle Co, we’re here to support your build from the ground up.