Rock River Arms Completed Pistol Upper Receiver Mountain .223/5.56mm 10.5 Inch Barrel 1-9 Twist 1/2-28 Threat A2 Flash Hider Black

Rock River Arms

Overview

The Rock River Arms Completed Pistol Upper Receiver features a 10.5-inch barrel chambered for the 5.56 NATO caliber, making it suitable for short-barreled applications. With a 1:9 twist rate, this upper is designed to stabilize a variety of bullet weights, providing versatility in ammunition selection. This upper receiver is often found in compact builds aimed at enhancing maneuverability while maintaining reliable performance.