Extremely accurate - Primary Weapons Systems MK111 MOD1-M .223 Wylde, 11.85in bbl Upper Receiver

Tested this upper receiver with over 500 hundred rounds on the first range trip with only a little lubricant on the bolt and some internals. The only issue that I had was a failure to feed on some steel case ammo that is over 20 years old. When using a suppressor, the upper ran very clean and well without any gas coming back in my face. I had to use setting 3 when running suppressed or the bolt would fail to go into battery