I think different people hitting the target at different places with the same sights has to do with geometry. No two people are going to hold a gun (or their eyes/body) exactly the same, and tiny differences in the angle between your eye and the sights are going to work out to much more substantial differences down range. The length or your arms, the length of your neck, etc are all going to create minute differences in sight picture.
As far as things changing after cataract surgery, that's not super surprising as the surgery probably slightly changed the optic "sweet spot" on the surface of your eye. You probably - without noticing - have your eye held a little differnt than you did before.
si vis pacem para bellum
Last edited by dayman; December 21, 2012 at 01:42 PM.
Reason: I apparantly left "think" out of my first sentance