Mounting Scopes

[Howa 9700]

Some years back when I got into air rifles, I first became aware of the challenge of mounting scopes. The need to get the vertical crosshair in perfect alignment with the rifle's bore. I went so far as to create some graphics for it. This would be ideal....such that when a bullet is fired from the bore, assuming no wind drift or any of that stuff, the bullet would rise and fall thru the vertical crosshair. This is what we all think happens......or at least hope happens. Or at least should be the goal.




But unless the bore and vertical axis of the scope are in perfect alignment, that is not going to happen. If the scope is slightly out of plumb, this condition is created......you may have crosshairs in vertical alignment, but bore is offset to one side or the other. There would only be one point along the way where the two cross, and that is the distance you have sighted in for. Short of that, or beyond it, it will be off. The exaggerated version of this would if the rifle were fired horizontal instead of vertical.



So the challenge, for me anyway, has been to find a way to get the rifle and scope singing off the same sheet music when mounting scopes. The method I came up with on my own was to hang a visible plumb bob some distance out, the by bore sighting, center the plumb bob in the bore, and while doing that, rotate the scope until the crosshairs are in perfect vertical alignment with the plumb bob. When you get it all right, the two ought to be in alignment. Tried that recently when mounting a scope and for some reason, could never get the two in alignment.

So started giving some thought as to how to use levels, and eventually found there are products built for this purpose. The one I bought and used was made by Wheeler, which seems to be part of the Larry Potterfield shooting sports empire.

This one:

Professional Scope Reticle Leveling System | Wheeler

Professional Reticle Leveling System

www.wheelertools.com

Anyway, the process used by that seems pretty fool proof. Rifle is set dead level.......scope is then set to dead level on top of it to match. The vertical line on scope now close enough to the bore's center line, the error won't be noticed inside typical range of the rifle. Bottom line, I spent over an hour messing around trying to get rifle and scope synched up using my old methods and when I checked with this set of levels, found I was still off, and by a lot.

So this is my new way of mounting scopes. My old way wasn't hacking it.

 

[Howa 9700]

BTW, same problem with cant induced shot drift still exists if rifle and scope are canted to one side or the other when firing. What this situation cries out for is some type of level visible within the scope. Levels on the outside mean you have to look, then move back to scope. Don't know how hard it would be to build, but what would be nice is simple gravity pumb bob visible thru the scope. Like an "incline-o-meter".....or the level indicators used on airplanes.

 

[Chuck R.]

The issue with the method you describe is that often the scope turrets/caps aren't "square" or parallel either. usually they're close, but often "close" isn't good enough.

I prefer to level the rifle & mounts, then use the Caldwell barrel level to "capture" when they're level, I then use a plumb bob at 25yds. The plumb bob takes the turrets & caps out of the equation.

 

[Walkalong]

The issue with the method you describe is that often the scope turrets/caps aren't "square" or parallel either. usually they're close, but often "close" isn't good enough.

I prefer to level the rifle & mounts, then use the Caldwell barrel level to "capture" when they're level, I then use a plumb bob at 25yds. The plumb bob takes the turrets & caps out of the equation.

Yep.

 

[Howa 9700]

So sounds like my first plan wasn't so far off if I had substituted a way to lock the rifle level in place of the bore sighting half?

Some type of vice to lock it in place would certainly be helpful. The barrel blocks do the same as that half of the Wheeler level kit that clamps to the barrel. Even with the Wheeler setup, getting the gun level and keeping it there is not so easy without one.

 

[AlexanderA]

You're at the mercy of the holes on the receiver (for the scope mount) being drilled correctly at the factory. Presumably not a problem if there's an integral rail.

 

[LoonWulf]

You're at the mercy of the holes on the receiver (for the scope mount) being drilled correctly at the factory. Presumably not a problem if there's an integral rail.

Unless the rails crooked.......

Ive had holes miss drilled and receivers out of round. My only integral rail rifles have been 22s, a 527, and my S20.....so far so good there