'Tis my opinion that any "boxing" of a rifle scope up - right - down - left on its adjustments chasing a group on paper needs a rifle and ammo that one can shoot no worse than 1/10th MOA at 100 yards if they want to measure the scope's repeatability to 1/4 MOA with near 100% confidence. The shooter's errors plus the ammo and the rifle's errors are part of the group.
A cheaper and more accurate way is to put an optical collimator in the muzzle, set the scope's power to maximum, adjust the scope's reticule on the collimator's reticule, then box the scope in 1-click, 4-click and 20-click legs. 1/4 MOA errors are easily seen. Especially when only one click is made then reversed; a lot of scopes won't move the reticule back at all with a single click one way then back one click. Make a 1-click box and watch what happens; you may be surprised.
Then with the scope dead on the collimator, change the power ring from max down to min them back up again watching the scope's reticule make a figure 8 on the collimator. If that figure 8's less than 1/4 MOA across its widest points, you have a very repeatable scope when its power's changed. Few do this to less than 1/4 MOA error. Which is why fixed power scopes are typically more repeatable than variables.
I still think Weaver's Micro Trac adjustments are the most repeatable internal adjustments.
US Navy Distinguished Marksman Badge 153
Former US Navy & Palma Rifle Team Member
NRA High Power Master & Long Range High Master
NRA Smallbore Prone Master
Last edited by Bart B.; July 7, 2013 at 12:45 PM.