You can cant the RIFLE as much as you want as long as the SIGHTS (crosshairs) are vertical.

Of course, you have to cant it the same every time, but this is also true of ZERO cant. Either way you need a good bubble level (or an electronic “Level Grouse”).

Footnote 1: For the scope to be “vertical” means that the elevation adjustments track straight up and down, which may or may not be the same as the crosshairs being vertical, especially if you have a Leupy.

Footnote 2: With enough cant you may need to worry about the horizontal difference between the center of the scope and the center of the bore. In the most extreme case (the rifle laying on its side), this could be a (fixed) displacement of 1.5-2.5 inches (the “height” of the scope above the bore). This could complicate cold-bore egg shots at unknown distances. This won’t matter if: you get sighters, shoot only at known distances, shoot at big things (say, elk or Palma targets), or don’t care if you hit the X ring (i.e., benchrest shooting for group size).