Originally Posted by Brian.Samson
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.
Thanks Brian, I have some cheap Hawke scopes lying around that insist on moving zero every dozen or so shots, I will mess about with one then cut it up. Incidently I did cut a cheap scope up some months ago and was appalled to see a very flimsy leaf spring in situ, no wonder that damn thing was unreliable with a boinger.