Re: Best method or system for leveling a scope???
I use a method similar to BigNGreen. The main focus being on the TRAVEL of the scope and not the reticle. No matter how precise or perfect you get your reticle plumb with the earth, if your sope does not track in the EXACT same plane as the reticle, you will be off left/right at long range. For those of you who use the reticle for holdover, then the reticle should be your primary focus. If you dial for yardage, you need the tracking of your scope to be your main focus. I don't have the luxury of owning a nightforce, or other high end optics. I do know the two Leupold VX3's I have, suffer from some reticle cant in relation to the travel of the scope.
So here is what I do.
I install an anti-cant device on all my long range setups. Although they are cheaply built, I prefer the tall flip-up style as in the 4th picture posted by Woods. I use my cleaning vise, and make sure the gun is very stable and won't move while dialing the scope up and down. At 100 yards, I draw a 4' line on paper, and use a 4' level to make sure it is perfectly level. Then I dial my scope to the top of its travel and line up with the top of the line. (don't forget to adjust the paralax to take out any optical error). With the crosshairs verticly eyeballed on the line, I install the anti-cant device so that the level reads perfect and snug it down. Now dial to the bottom of the scope travel and see which side the center of the crosshair ends up on. If it ends up on the right side of the line, loosen the anti-cant device and rotate counter clockwise (from the shooters position) slightly. If it ends up on the left, rotate clockwise. Then redial back to the top, setup again, and retest. It will most likely take a few times to get it absolutely perfect.
Now your anti-cant device is setup exactly in line with the travel of the scope. The anticant device is now a permanet fixture for this scope, and should never be removed or adjusted or you will have to repeat the process. At this point, I adjust the scope/reticle from a prone shooting position off bipods. I line up on a target, find a comfortable hold with good cheekweld, and look to see if the anticant device is level. I repeat several times and adjust the scope in the rings slightly so that in my natural hold, the anticant device ends up reading level. Then I lock down the rings, and I am done.
I will probably get a lot of people that disagree with me on the next point. It really does not matter if the SCOPE is level or inline with the bore at all. As long as you use the anti-cant device when you shoot, your bullet will travel with gravity, and in line with the travel of your scope. Example: Lets say after setting up your anti-cant device and your scope travels perfectly up and down with gravity. Lets pretend to loosen the rings and twist the scope something severe like 15 degrees clockwise. Now the gun would need to be rotated counter closkwise 15 degrees for the anti-cant device to read level. Thus the centerline of the bore is to the right of the scope ( I will guess about a 1/4"). So if you zero your gun at 200 yards, at the muzzle your bullet impact would be 1/4" to the right. Then at 400 yards you will be 1/4" to the left. At 1000yrds you would be off about 1". Keep in mind this would be very drastic cant and all of us will do a much better job of eyeballing the scope to within a few degrees of being directly above the centerline of the bore.
The tool used by woods is awesome for setting the scope directly above the centerline of the bore. I might have to make one!
This is how I learned to do it after wasting a lot of time getting reticles perfectly level and later finding out my scope did not track in line with the reticle. I hope this might help some of you.