A short time ago, I mounted an old 3X9 scope on my Marlin 336 in order to work up a 'best load' for my .30-30 that I'd never reloaded for before. I've had many standard hunting scopes over the years, and I usually bore sight the scope before going to the range to fine-tune it for my typical 100 yard zero. What I found, while trying to get the scope/rifle on paper at 25 yards was something I'd never really thought about before: the exact number of clicks to move a bullet impact one inch at various distances. Knowing that my impact will change 1/4" at 100 yards for each click, here's what I re-discovered: For 25 yards - to move the impact 1 full inch took 16 clicks For 50 yards - to move the impact 1 full inch took 8 clicks For 100 yards - of course the scope needs 4 clicks to move 1 full inch. The scope was off about 3 full inches both windage and elevation, so it took 48 clicks to move the impact to the center of the bullseye on a target set at 25 yards. I used to just fire a group, and guestimate how many clicks to adjust the scope, fire again and repeat the same thing. Using the formula about should save a bunch of ammo to zero. You still need to know the trajectory at different ranges for your caliber/rifle, but this should help. At least I hope so.