Originally Posted by TWR
Armalite is one of the lowest out there at 1.25"
http://www.maxicon.com/guns/optics/one_piece/ar15_onepiece_mounts.htm

Well that explains a lot. My cheapy Nikon is 4-14X so you can't really see it. But if the light is right then it distorts the target or whatever you're aiming at.