I finally got my big dot sights mounted, this last week and got out to the range yesterday. I formed the lollipop that is presented on XS's website
http://www.xssights.com/pix/sightimages.gif and also here Shooting Illustrated's Guns and Hunting - NRA
Well after I was done shooting I was consistantly 4-6" below the point of aim. I covered the target with the dot and cradled it. I called XS and they said I was doing everything correctly and I had the correct rear and front sight setup, 0.340 in the back for commander slide sized 1911's(mine is a CCO formate springer, 4" barrel).
Has anyone had any issues with these before? I have only used 3dots but I really like the wedge setup of this sight.