The Rise Armament 6 ARC Upper Receiver (brand part number RA6ARCCUBLK18) is a complete 18-inch upper assembly built for the 6mm Advanced Rifle Cartridge, a caliber designed to deliver long-range performance and flat trajectory out of a standard AR-15 platform. The 18-inch length gives 6 ARC loads the barrel time needed to reach their intended velocity, and the aluminum receiver keeps the completed build manageable in weight for a rifle that will spend real time on a bench or in the field at distance. This upper drops onto a compatible AR-15 lower to complete the build.

Key Specifications

• Chambered in 6 ARC, a modern long-range caliber designed for flat trajectory out of an AR-15 platform.
• Barrel length measures 18 inches, giving 6 ARC loads the length needed to reach their intended velocity.
• Rate of twist is 1:7, matched to stabilize 6 ARC’s higher-BC bullet options.
• Style is listed as Complete, indicating a fully assembled upper ready to mate to a compatible lower.
• Receiver material is aluminum, keeping the complete upper manageable in weight for long-range use.

Frequently Asked Questions

Is this a complete rifle? No, this is an upper receiver assembly only with no lower receiver included. It ships without an FFL transfer and needs a compatible AR-15 lower to complete a rifle.

What makes 6 ARC different from other AR-15 calibers? 6 ARC is designed specifically for long-range performance and a flatter trajectory than typical AR-15 offerings like 5.56, while still running through standard AR-15 magazines and lowers.

Does this upper come with a bolt carrier group? Confirm bolt carrier group and charging handle inclusion at checkout, as caliber-specific bolts are required for 6 ARC.

Buy the Rise Armament 6 ARC 18in Upper Receiver

Order this Rise Armament 6 ARC upper receiver from a Lubbock, Texas gun shop for your next long-range AR-15 build. Browse more complete uppers in our AR15 uppers selection.