Aero Precision

Overview

The Aero Precision M4E1 Assembled Gen 2 Upper Receiver is a complete upper designed for AR-15 builds, featuring an 8-inch barrel optimized for the 300 Blackout caliber. With a pistol-length gas system and a 1:7 twist rate, this upper provides reliable cycling and stability, making it suitable for a variety of ammunition types. This upper is commonly used in builds focused on compact configurations and subsonic performance, particularly in 300 Blackout setups.