New scope test that anyone can try

[BoydAllen]

Today I saw a Youtube video demonstrating how to align a rifle scope by using a flashlight shining through its objective to project the reticle onto a wall. After watching it, I saw a that there was another video on doing a tall target test (shooting at the range) to test whether a scope's reticle is aligned with its turrets. This got me to thinking. With your rifle set up to project its reticle on the wall, and accurately leveled with an accurate level on top of the scope's vertical turret, or its cap, the projected reticle could be compared to a plumb line so see if they were perfectly parallel. If they were not, you would be changing windage slightly when making an elevation adjustment. If any of your try this, please post your results. What we are trying to do is detect a manufacturing defect, not do an adjustment.

 

[mikecr]

This could show optical offsets, or skew for a standard crosshair type reticle.
What both X & Y mechanical adjustments do from there should still be tested(box).
I don't see where a turret top matters.

 

[BoydAllen]

This could show optical offsets, or skew for a standard crosshair type reticle.
What both X & Y mechanical adjustments do from there should still be tested(box).
I don't see where a turret top matters.

The assumption is that the top of the turret is at a right angle to its axis. By leveling the scope at this point and comparing the projected image of the vertical cross hair to a plumb line, we can see if the reticle is aligned with the turret. If it is not, the line that the intersection of the cross hairs follows as adjustments are made will not be straight up or down. Some windage adjustment will be put in with a vertical adjustment. The slick part of this method is that it can be done without firing the rifle, indoors.

 

[500Stroker]

Today I saw a Youtube video demonstrating how to align a rifle scope by using a flashlight shining through its objective to project the reticle onto a wall. After watching it, I saw a that there was another video on doing a tall target test (shooting at the range) to test whether a scope's reticle is aligned with its turrets. This got me to thinking. With your rifle set up to project its reticle on the wall, and accurately leveled with an accurate level on top of the scope's vertical turret, or its cap, the projected reticle could be compared to a plumb line so see if they were perfectly parallel. If they were not, you would be changing windage slightly when making an elevation adjustment. If any of your try this, please post your results. What we are trying to do is detect a manufacturing defect, not do an adjustment.

Boyd how about a link to the youtube video's.
Thanks in advance
Jim K
PS Not to change the subject but I would like to see you do a video on tuning 10-10 scales

 

[eric32]

https://kahntrol.com/leveling-a-reticle/

check'em out

 

[T-shooter]

https://kahntrol.com/leveling-a-reticle/

check'em out

That will level the reticle but will the centerline of the scope be on the same vertical plane as the centerline of the bore?

 

[hoz53]

The assumption is that the top of the turret is at a right angle to its axis. By leveling the scope at this point and comparing the projected image of the vertical cross hair to a plumb line, we can see if the reticle is aligned with the turret. If it is not, the line that the intersection of the cross hairs follows as adjustments are made will not be straight up or down. Some windage adjustment will be put in with a vertical adjustment. The slick part of this method is that it can be done without firing the rifle, indoors.

I see what youre saying. this is a good idea. NF says in the manual the recticle is perpendicular/parallel to the flat on the bottom of the turret housing. that could be checked the same way. a steel plate set up with some old scope mounts would make it much easier to level indoors like you suggest. Thanks

 

[BoydAllen]

That will level the reticle but will the centerline of the scope be on the same vertical plane as the centerline of the bore?

I have a Verticle Reticle Insturment that does that. I found this thread with pictures.
http://www.longrangehunting.com/forums/f18/best-method-system-leveling-scope-64348/

 

[Bart B.]

I've tested scope adjustment axes using an optical collimator in the muzzle. Zero the scope's reticle on it, then move the W and E knobs across their range. Watch the collimator reticle's displacement from a reticle wire. if it moves away from it, that reticle wire is not parallel with the adjustment screw flat the inner (erector) scope tube slides across.

One scope had perfect tracking for the vertical reticle wire. Horizontal one had about 1 MOA error at its limit towards the windage knob. Proof to me the reticle wires were not at right angles apart, or, the adjustment knob/screw axis was not at right angles apart. Using that scope to look at a framing square 50 feet away showed its wires were not exactly 90 degrees apart. No big deal, in my opinion.

Most scopes have a greater adjustment range between limits up and right than down and left.

 

[brian y]

I use a one piece base and use the feeler gauge method, Works well.

 

[Bart B.]

What both X & Y mechanical adjustments do from there should still be tested(box).

Agree.

Box the scope using an optical collimator in the muzzle. Much more precise than shooting bullets. 1 or 2 clicks for each side of the square. Then 10 back and forth each way.

 

[BoydAllen]

There is only one problem with collimators. I would never put one of those spuds in the muzzle of one of my barrels.