When calibrating scopes using the tall target test by shooting groups always felt there were several variables that were difficult to control and would mount the scope on my most accurate rifle for the test. Being a bit on the OCD side I built a calibration stand in my shop out of 2.5" receiver tubing, 2.5" angle and 1x2 tubing. Leveling screws from PMA tools. Haven't used it yet but will try it in the next couple of weeks on scopes and Charlie TARAC.
