Trying real hard to like the trijicon MRO. But my astigmatism forces me to use the rear back up sight with the red dot. Unfortunately, this causes a 6 inch parallax shift at 100 yards. I have considered switching the 1/3 lower mount for an absolute cowitness mount. Part of me thinks that this will work, part of me also says quit on the MRO and get a different optic. Perhaps a lpvo that will agree with my astigmatism better. This is currently mounted on a Colt 6720. General purpose use carbine for my children....