Proper way of mounting a scope on an AR, is there?

[WS6]

Badger Dead Level and a plumb bob, flash-light, torque wrench, feeler gauges, acetone, Loctite 222ms, and patience.

[hotrodder636]

The Arisaka tool is really nice and easy to use.

This is what I have used, beyond bubble level method. Pretty good results to date.

[OrbitalE]

I run bubble levels on all my scopes. I am no expert, but people who are, Todd Hodnett for one, emphasizes the importance of the scope being level with the world over being level with the gun. Personally, the longest I have ever shot was 700y and the scope was level to the gun... well... as level as a cheap Home Depot line level can gauge. I am sure if the scope is off by 30* to the bore it would become a problem, but a few degrees here and there? I don't think it would become a problem. Just my uneducated $0.02

If you don't naturally cant the rifle then the scope is level to the world when it is level to the rifle. A few whole degrees (in the single digits) of cant exponentially increases error (many inches) at distance.

[WS6]

Slippers is awesome, and Arisaka makes good stuff, but I think I gave my wedge-leveler deal away. I used it once and the results were poor. The device is correctly made, it was just user error. I never could get it to "do right for me".