Originally Posted by RobF
So what that would suggest is that the rig wasn't set up level in the first place.
I interpret your first post such that you did the lathe testing after the Worlds, and not using your comp rig.
So yep, I would make sure your comp rig has the barrel straight with respect to the dovetails. Then put the scope on and make sure the scope vertical cross hair is bang on using a plumb line. You can add a bubble mounted to the scope, if you wish, as a check.
Then test indoors, and if the physics are right then the poi's should fall within a couple of mm's of the vertical line.