Originally Posted by pathfinderheli
Thanks... That was dumb of me... I should have probably looked there first... I know there are issues with the URX II and the KAC proprietary mid length... I think they have fixed that issue with the URX III...
The issue was with the mid length URX and mid length gas systems. The gas block was where the integrated front sight is, and that area dips down inside the rail a little bit causing a conflict.