Optic center of scope

Mirror is much easier way to accomplish same thing. Works every time 

I did the all the way in then all the way out counting clicks, then returning back to half way. What seemed strange to me was, the up-down top turret had a total of 52 clicks while the left-right side turret had a total of 240 clicks. Is this normal, such a big difference?

It's an Athlon Talos 3x12x40 scope btw.

Click to expand...

What you did got you to the "mechanical" center of the scope. Not the "optical" center.

The "mirror" technique will get you closer to the optical center. And yes, sometimes, quite often in fact, they are not the same.

Choose one and go from there. Personally I center mechanically first, then *sometimes* check via the mirror method to see how much difference there is.

Mechanical centering is good because it keeps the scopes erectors as close to center as possible which *should* make them more stable.

As for the difference in clicks... here are the specs for that scope from Athlon Optics. Looks like you should have 240 clicks lock to lock for both windage and elevation. 60/.25 = 240 and 4 complete rotations of the turrets lock to lock 60/15 = 4

I thought it might be a zero stop that was already set, but...

Looks like this scope does not have a zero stop capability, so you may need to contact Athlon and send it back.

To check optical center of the scope you hold the end of it against a mirror. Now look thru it and you will see the crosshairs and a ghost image of crosshairs. Line them up by twisting your turrets.

To check optical center of the scope you hold the end of it against a mirror. Now look thru it and you will see the crosshairs and a ghost image of crosshairs. Line them up by twisting your turrets. 

The "end" is which end, ocular or objective? Every time I have tried this trick, the mirror is so dark from putting the objective lens up tight to the mirror, I can't see squat. What am I missing??

mike

I did the all the way in then all the way out counting clicks, then returning back to half way. What seemed strange to me was, the up-down top turret had a total of 52 clicks while the left-right side turret had a total of 240 clicks. Is this normal, such a big difference?

It's an Athlon Talos 3x12x40 scope btw.

Click to expand...

A possible reason - the rated adjustment range is only valid when the opposite turret is mechanically centered. If you did the up-down first, you would need to go back to it for an accurate count after mechanically centering the left-right turret.

1) center the up-down turret.

2) count the left-right turns/clicks and then recenter it.

3) count the up-down turns/clicks.

There is a mirror method for aligning the vertical reticle with the bore. But there is also a different mirror method for "optically centering" the scope. If you only plan on shooting at one zero distance, there might be some benefit to optically centering. But if you click or use reticle hold over to shoot at different distances, there are more benefits to mechanically centering the scope.

To check optical center of the scope you hold the end of it against a mirror. Now look thru it and you will see the crosshairs and a ghost image of crosshairs. Line them up by twisting your turrets. 

The "end" is which end, ocular or objective? Every time I have tried this trick, the mirror is so dark from putting the objective lens up tight to the mirror, I can't see squat. What am I missing??

mike

Click to expand...

The objective end against the mirror. The mirror I use is an old very thick glass mirror. It seems to let light in enough to see the crosshairs.

"The objective end against the mirror. The mirror I use is an old very thick glass mirror. It seems to let light in enough to see the crosshairs. "

Thank you! Just wanted to be sure I was doing it correctly.

mike

It also helps if you have a illuminated scope to turn it on..

Also, set your zoom to the lowest, and your parallax to infinity, when using the mirror technique