Originally Posted by what barn door
I don't understand why using the centre of the turret adjustable range won't work for centering the errector tube? unless it's a poor quality scope and things have not been assembled symetricaly?
Not sure I understand why either, but it's been true of every scope I've ever owned including some very expensive glass.
Try it, if you have a spare scope laying around. Centre the turrets by counting clicks, then either try the mirror method or the v-block method to see just how far out of optical centre the turret method is.
Incidentally, Leupold optically centre their scopes at the factory using the mirror method before they ship scopes out. That's where I first heard about the mirror method after speaking to them directly.