Rock River Arms Completed Upper Receiver National Match A4 .223/5.56mm 20 Inch Barrel 1-8 Twist 1/2-28 Thread Free-Float Handguard A2 Flash Hider

Rock River Arms

Overview

The Rock River Arms Completed Upper Receiver National Match A4 is a fully assembled upper designed for the AR-15 platform, featuring a 20-inch barrel with a 1:8 twist rate that stabilizes a wide range of bullet weights. With a thread pitch of 1/2x28, this upper accommodates standard muzzle devices, and the A4 receiver type provides a flat-top configuration ideal for optics. This upper is commonly found in precision-oriented builds, especially those intended for competitive shooting or long-range engagements.