A bubble level or reticle level as must have gear

[Litehiker]

Mike, a 10, 20 or 30 MOA base is not horizontally canted, it is vertically angled to give you greater vertical shot placement than your scope's vertical turret can accommodate. I think this is what you mean when you say "canted".

True canting is when the scope crosshairs are not true vertical/horizontal either when the scope is installed in the rings or when you lean the rifle when shooting.

If a reticle is accidentally installed canted at the factory even if you install the scope on your rifle so the vertical crosshair is true vertical it will shoot off vertical left or right as you adjust the vertical turret to shoot further distances. In this case the remedy is to return it for a new scope.

Eric B.

 

[Kansaswoodguy]

http://precisionhardcoregear.com/arlevel.php

I like these particularly for AR's but they make others as well

 

[stirner]

I have 2 Accu/Level Articulating Scope Levels. One is mounted on an AR with a 30mm scope tube, the other on a Kelbly action with a 34mm tube. I like these because they are easy to install, and when the bubble is extended it is easy to read. When not in use, it folds on top of the scope and out of the way.

 

[7magcreedmoor]

A bubble level on your rig changes "cant miss" to "can't miss".
Sorry. I just couldn't resist....

 

[Poorboyr]

Levels are a must for long range shooting. Check out US Optics, they can put a level in the reticle. It works pretty well.