Originally Posted by skires
Do you mean optical centering?
Most people don't bother.
Technically it will help as it will mean that you are looking at your cross hairs through the very best part of the glass of the lenses. So optically the picture should be at it's best.
Also by having the cross hairs centred through the very centre of the scope can mean that you should get your poi's along a true vertical line all through the ranges.
So if you have your PA ( focus ) set to 25 yards then optically centre it at 25 yards. You then shouldn't get any 'crossover' at extreme ranges but the scope needs to be mounted perfectly in line with the barrel. Most mounts take the scope off true. So ideally you have your scope optically centred and then the mounts are adjusted so that the scope lines up perfectly with the barrel.
Is this what you mean?
yes that's what Im talking about.