Primary Weapon Systems

Overview

The Primary Weapons Systems MK111 Pro Upper is a complete upper receiver designed for the AR-15 platform, featuring an 11.85-inch barrel optimized for 5.56 NATO ammunition. The mid-length gas system ensures smoother cycling and reduced recoil, while the 1:8 twist rate provides versatility in stabilizing a wide range of bullet weights. This upper is often found in builds aimed at compact versatility, making it a solid choice for close-quarters engagements or as a lightweight option for a variety of shooting applications.