10.5 MK-18 Upper A4 1/7 QPQ
We started with a 5.56 10.5" 1/7 twist barrel for this build. The barrel is made from 4150 machine gun steel with QPQ finish. The upper receiver is T marked and is type 3 hard coat black. This does have M4 ramps. The Flash hider is a A2 this is for PISTOL OR SBR USE ONLY. It is also made of chrome-moly steel and HP tested. Our barrels are Mil-Spec or better. We recommend a 55gr or 62gr bullet for best accuracy. The front sight is a A2 F-Marked with bayonet lug and attached with taper pins. Gas port size is .073.