Boresighting Tip

[silent2012owl]

I installed an older scope I had removed from a gun I had sold, on my new rifle.
Consequently I didn't know how far off optical center the scope adjustments were.

When trying to boresight it on the new rifle I found that I didn't have enough adjustment range and my weaver mounts and rings have no provision for any windage adjustments.

Did some searching on the net and found a very easy procedure to optically center a scope for maximum adjustment range.

1. go to your bathroom mirror and place the exit lens of the scope squarely on the glass and hold it there. (Don't break the mirror )
2.Make sure your bathroom is well lit and look through the scope. You will see two cross hair images, one real and one reflected.
3. use the elevation and windage adjustments to superimpose both images so that you are left with just one crosshair image.
4. your scope is now optically centered.

My scope was way off center in both directions.

After doing this procedure I repeated my boresighting exercise. The windage was bang on with the elevation only needing about 10 clicks for a perfect boresight at 25 yards

 

[kamlooky]

This sounds like one heck of a tip.
New to my eyes for sure.
Thanks.

 

[Slowbalt]

Great tip!

 

[jaydog]

Interesting- I've got a crappy old Tasco on the shelf I'm going to try this on tonight.
I'm assuming this will save me the hassle of turning the turrets all the way in one direction, counting the clicks going back all the other way and then backing up half that count?

 

[archer2u]

will give it a go thanks for the tip

 

[silent2012owl]

Interesting- I've got a crappy old Tasco on the shelf I'm going to try this on tonight.
I'm assuming this will save me the hassle of turning the turrets all the way in one direction, counting the clicks going back all the other way and then backing up half that count?

Yep, no need to count any clicks. Just superimpose the 2 images and you're good !

 

[KDX]

Good tip. Thanks.

 

[Dogleg]

After you centered your adjustments, did you then mount it in non adjustable rings? What exactly did you gain? The scope settings end up in the same place as if you had done nothing at all.

 

[silent2012owl]

After you centered your adjustments, did you then mount it in non adjustable rings? What exactly did you gain? The scope settings end up in the same place as if you had done nothing at all.

It's not that simple. Before centering the scope the windage adj. was out a good 12 inches. Adjusting the whole windage range ( 3 whole turret turns total ) only reduced it to about 9 inches. That's with the barrel bore centered on the target at 25 yards.
When I did the optical centering, I found the windage adjustment on the scope to be WAAAY out. Took about
4 1/2 full turret turns to center it. Had to go way past of what felt like a turret stop (stiff section) but turned out not to be after all.
The previous adjustment for my other rifle must've been way out.
Anyway, after optical center was adjusted, the windage was right on and elevation just needed a few clicks for boresight zero.
Never touched the scope mounts and rings !

 

[Juster]

Centering your scope may not give you maximum useful adjustment range, since gravity may have you going up more than down. Apart from that, great stuff.