Nikons spot on software is pretty awsome. You can plug in every aspect of your weapon and I will say they are dang close. Close enough that I could buy a rifle and scope zero it at 100 do my homework on the spot on software and hit a 12" area at 500. Not perfect but its dang close for some basic computing
Thanks buckslayer, actually I just downloaded that Nikon Spot-On chart the other day. I went back to look at it again and things are starting to come together. Thanks for the reminder - duh.