Easy Centering of a Scope's Adjustment Dials with a Mirror

[quickdtoo]

From the Leupold Answer Guide.

Tim


Centering of a scope's adjustment dials

The elevation and windage adjustments of a scope are easily centered. Place a small mirror against the objective end of the scope. That would be the end farthest from your eye as you look through the scope. Make certain that the mirror is large enough to cover the entire objective. It must also be flat against the objective. With the scope's power selector ring set at the lowest magnification, look through the eyepiece as you would while aiming at a target. If the scope's windage and elevation adjustments are off center, you will see two images of the reticle (cross-hair). To reach the center of the adjustment range, simply turn the elevation and windage dials until you see only one image of the reticle.


http://www2.leupold.com/resources/MyInfo81/Answerbook/AnswerbookPage.aspx?AnswerbookPageId=771f440e-a190-4499-89f2-cca921379b25

[kyelkhunter3006]

That's pretty nifty!  I'm sure that I won't remember it though.   

[Graybeard]

So what's wrong with counting the clicks or just checking the manufacturer's specs for that info and turning it all the way one direction and clicking back half that number? I can count while on the range but can't say I've ever had a mirror with me out there.

[charles p]

How does light get into the scope with the mirror over the objective end?  Sounds like a great idea.

[kyelkhunter3006]

It must reflect off of the mirror into the tube.  The objective is flat against the glass, but not against the reflective surface of the mirror.

[GRIMJIM]

Stupid question here but what is the purpose of centering the scope? It doesn't have anything to do with sighting it in on the gun, or am I mistaken. Is it a good idea to do it before you transfer the scope to another gun? Is this just in case the knobs fall off? I just wondered.

[quickdtoo]

When mounting a scope, it's desirable to have the reticle in the center of the focal plain, that's where the best resolution and clarity happens, toward the edges isn't as clear, if you center the adjustments, you're centering the reticle within their adjustment range, if you have to adjust it a lot to bore sight it, you know right away that something is out of alignment, it could be the base(s), mounting holes out of alignment, bad rings or the bore is off center. If it's off a lot, Burris Signature rings with offset inserts can take care of it . Knowing you used a lot of windage or elevation adjustment just to get bore sighted will also tell you may not have much left to make adjustments zeroing at the range, something that would be nice to know before you're sitting in front of your target scratching your head when your turret adjustment runs out of travel!!

Count clicks if you want to, you can also use a V-block, the mirror method is so easy tho, best done before you mount the scope, it's easier to get the light angle correct.  I mount scopes at home on my workbench, I like to shoot at the range and not play with my scope counting clicks!! 

Tim

[XB40]

If you have ever counted 250 clicks without any interference, then counted clicks to 125, again, without ANY disruptions, you are more fortunate than I. This works and is by far easier. Good information!

[PartsMan]

I keep a small mirror near my bench for this very reason.
I have done it with the mirror on the bathroom wall though.
As long as you have it good and bright in the room you can see the crosshairs.
That's all you need.

Works better for me than the V block. Counting clicks is probably more accurate though.

[Glanceblamm]

Scope Repaired. Thanks quickdtoo!!

The scope was an older 4x32 (Universal Brand) that I had inherited back in the 80's. I had used it on two different rifles and would put it on, or take it off a third depending on my mood.
No problems till I let my Son try it on his model 60 and he and my son-in-law took it out to sight it in. Elevation recticle is broke or stuck they claimed, wont print any higher than 6" below p.o.a they said. I found what they were saying was true and I tryed turning that elevation dial up & down while gently tapping the turrent but it did no good.

Three and a half months later I see this post and decide to check the centering as said by the posted procedure. Those boys must have really done some cranking on that scope because it was way off. I had to crank that elevation dial down several turns before it caught hold and I was able to get it centered on the vertical. The Hoizontal was not too bad and I got both sets of crosshairs to line up perfectly.
That was last night and I put the scope back on a rimfire today to check it out. It hit paper right at the start and I was able to get it zeroed quickly

I had (Centered) new scopes in the past but not by using the posted procedure which was fast and easy. What I would do is to make a couple of "U" shaped holes in a shoe box then place the scope in the holes and turn it round & round & round while looking through it and using the dials to correct that lopsided wagon wheel. That would work but it was quite tedious!

Again, Thanks For That Procedure quickdtoo! It was so fast and easy that it was worth trying and just happened to work. I should probably send you at least $35 but I am a little short right now

[quickdtoo]

Glad it worked for ya, it's saved me a bunch of time fiddling with scopes, that's for sure!!

Tim

[Glanceblamm]

I fired six shots in pairs of two on the quick 25yd sight-in and the Scope adjustment Gods must have been with me as the last two went into my target area of perhaps 1/4" square.
(Please note that there is only one God)
I noticed that the three pairs of two holes were either touching or overlapping...I knew that the scope was accurate but could not remember it doing this before so the centering may have enhanced the accuracy....I will have to try this on the 50yd range to be sure but it was one of those rare occasions that I had ran out of shells!

[Siskiyou]

Thanks for the information.  I thought I would test it by pulling an old scope out of the drawer.  I choose to use a bathroom mirror because it has three light bulbs over the mirror.  I was greeted by the image of two sets of crosshairs.  A few minutes later I adjusted it to one crosshairs. 

My next step was to call a brother and tell him about the process.  I would not be surprised if he has pulled out a scope and is checking it in the mirror.  His young son must think he has gone over edge.  And there maybe a lesson in it for him.

Thanks again.

[Tom W.]

I tried it on a Burris that I had on two other pistol barrels. Worked for me.

[AiredaleTerrier]

This one needs a bump...Thanks Tim, had always wondered where my second hand Tascos were at...great tip!

[Dave in WV]

You can count the clicks, which is more accurate, but the mirror method is much faster to get the scope close to center. I've used both methods and the mirror method is very  close.

[r29l20]

Counting clicks ? just mark your starting point and count the revolutions then devide in half. You must start at the very end, one way or the other, of course. Also that's mechanical center, you must do the mirror trick, for optical center. Sometimes they do come out different

[stubshaft]

I swap scopes alot between my Tenders and Encores, great tip!