The thing that always got me with holdover is that I never knew how much to hold over, at different ranges. If I know I have 12" of hold over at 400 yds, how far do I hold over at 372 yards? 11"? How about 421 yards? 13"? Now, given I really am an imperfect guy, I'd venture when I pulled the trigger, I could actually be holding over anywhere in the range of 8-16", when looking at a deer at 400 yards. Where is that going to send the bullet?