Placement of Reese standard bed rails?

OK, Kevin-0, from the rear of the bed it is26 ½", and the rails are 22" between them. Again I did not have a hitch, I purchased a Pullright Superglide later when I purchased the fifth wheel. I cut the bed liner, so the rails sat flat on the metal bed. I used the above measurements to locate the rails, then drilled down thru the bed, and used the bolts to locate the frame brackets. Not a particularly hard installation, but take your time, measure twice, cut once! You are not playing horse shoes, so almost does not cut it! When finished, the super glide sits perfectly, with the pin just in front of the rear axel.