Rock River Arms Completed Upper Receiver A4 9MM Luger 7 Inch Barrel 1-10 Twist 1/2-36 Thread Free-Float Handguard A2 Flash Hider Black

Rock River Arms

Overview

The Rock River Arms Completed Upper Receiver A4 is designed specifically for AR-9 builds, featuring a 7-inch barrel chambered in 9mm with a 1:10 twist rate, which helps stabilize a range of bullet weights for improved accuracy. This complete assembly includes a free-float handguard and an A2 flash hider, making it a solid choice for builders looking to enhance their firearm's performance while maintaining a sleek black appearance. This upper receiver is often utilized in compact builds aimed at close-quarters use or competitive shooting scenarios.