rhe vari-x III's had another scale on the power ring to tell you the inches at that power from the crosshair to the thick part of the plex, I used it to make my longest holdover kill at 626 yards, been so long ago I forgot most of the details. that's why I don't post much about it, without the facts of what I did to make the shot I'm defenceless when the flaming starts.
RR