The way the vltor rail raises the eotech the buis wont cowitness. Doesnt bother me since the irons are backup and I never saw the point in crowding the eotech field of view. Thought that was sort of the point of the nice big window. Also..always felt like the eotech was a little low on stock receivers so its a win/win. What model is your sight? Its suppose to work with 511,512,551, and 552