Re: Levels: Checking&Using&Specs for scopes
I use a slightly different method that you may want to try. I find it very repeatable.
If you have a benchrest stock, or one that will stay put on a relatively hard surface, try leveling the table you place the rifle on, (this assumes you have the action straight up/dn in the stock) then look through your scope at a building somewhere. The building is your reference for the crosshairs to be plumbed to.
Be certain the scope is centered in both planes before you set it as the crosshairs will "bend" at the edges of adjustment.
After getting the scope square, CAREFULLY tighten the rings both sides simultaneously so as not to disturb the scope. Recheck till it's relatively tight, then finish torqueing the screws. I've had mine off my match gun countless times in the last year and it's dead on the money every time. Even worked after being rebarreled. I DO NOT resight the gun.
If you have something that you disassemble and reassemble enough times, sooner or later, you'll have two!