Anyone know what the diameter is of the gas block on the Colt 14.5" M4 barrel for models R0977 and LE6921? Supposedly the two models use the exact same upper receiver group, so it should be the same (Tina at SAW told me this.)
I am just curious because my when I put the upper on top of my Model 653 lower, it shoots a noticeable slower rate of automatic fire when compared to my Bushmaster uppers. The Bushmaster uppers I have used are .750" diameter and are the 14.5" M4 barrel and their 11.5" barrel.
I am just curious if mil-spec is using a smaller diameter than most commercial AR15's?