I have an old Burris 6x24 adjustable objective scope that I want to mount on my air rifle. It has 1/4 MOA clicks.

It was put away years ago because it runs out of windage adjustment to the right; at twenty yards, in my driveway, the point of impact is about 2 inches to the left of the POI when the windage dial hits the limit.

Burris Signature XTR Rings with patented Pos-Align Offset Inserts arriving this weekend.

It comes with a set of eccentric ring inserts marked + or - 5, 10 and 20.

As per the instructions ( https://www.burrisoptics.com/s...ringsinstruction.pdf ),

"if using the eccentric inserts to adjust elevation, a -20 insert in the bottom and a +20 insert on top of the front ring, and a +5 insert in the bottom and -5 in the top of the rear ring will equal 25 MOA of downward scope cant."

I will, of course, be starting with the inserts oriented laterally (not 45° off, as in the diagram) to try to get the crosshairs centered on the bullseye, while my scope's windage and elevation settings are centered at their adjustment limits.


Soooo...
which inserts should I select and to which sides would the + or _ be oriented to be closest to "on target" at twenty yards ?

This message has been edited. Last edited by: RichardC,

This is an interesting problem and I think I can help you with it. Before we start, when you say it's off to the right, is that on that specific rifle or another one?

For purposes of calculation, it's importantto kniw the distance between the front and rear rings, measured at the same point on each ring. Frot of rings, rear of rings or middle if rings. I usually neasure front to front.

Thank you for offering to help.
The new rings may arrive tomorrow, so I can mount and measure Sunday.

The scope had this problem on an older .22 and again on new air rifle.

Is that Burris scope "rated" for use on an air rifle? If not be prepared for it to dramatically fail from the abuse an air rifle will give regular optics. I note you say you used it before on one.....

quote:

Originally posted by bald1:
Is that Burris scope "rated" for use on an air rifle? If not be prepared for it to dramatically fail from the abuse an air rifle will give regular optics. I note you say you used it before on one.....

PCP air.rifle, I am not installing on spring piston gun.
It was on .22's and an AR in the past.

Richard, according to your prior statements, I believe it is possible that your scope body may be warped a little bit which would explain the major shift to the right.

When you get a chance, try the following: put the controls to the middle of the range. By that I mean, count the number of clicks or revs from extreme right to extreme left, divide by two and place the setting at that location. So if you have 4 revolutions between hard right and hard left, place the scope at 2 revs from either side. Do the same for elevation.

Once that is done, get a flashlight and put your scope, eyepiece first on a mirror and shine the flashlight in the objective and look into the objective. You should see the objective lens and then the erector tube at the FFP. If these image are not concentric, that will show the deviation in the main tube. My thinking is that you are going to find that the erector tube (the inner circle) is not going to be in the middle of the image, but rather, off to the left looking from the front.

If this is the issue we are addressing, we can try to remedy that with the Burris inserts.

Of course, if the scope is under warranty, you might send it in for repairs.

You should also download this PDF:
https://www.burrisoptics.com/s...ringsinstruction.pdf

Look at at the table at the bottom of the page and understand the role the ring spacing plays in calculating the offset. Yep, it's trigonometry all right, we'll be going through that.

There is an easier way of centering the adjustment dials than counting. This was the advice I got from a Leupold rep some years ago, and it was reportedly on their site at one time:

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.

NikonUser and sigfreund, I will try your suggestions.

Nikonuser, that pdf link is the same as in my first post.

I contacted Burris about repair and they insisted that it was my rifle having the scope mounting holes in the rifle off center, and to try the adjustable rings but they would inspect my scope if I really wanted and it would take 6-8 weeks, because, well, Covid.

quote:

Originally posted by sigfreund:
There is an easier way of centering the adjustment dials than counting. This was the advice I got from a Leupold rep some years ago, and it was reportedly on their site at one time:

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.

That works if the scope is fine. I'm thinking that the body is warped based on the fact the OP had the same issue on two or more rifles. My suggestion was just a quick way to see if we can identify the warpage.

quote:

Originally posted by RichardC:
NikonUser and sigfreund, I will try your suggestions.

Nikonuser, that pdf link is the same as in my first post.

I contacted Burris about repair and they insisted that it was my rifle having the scope mounting holes in the rifle off center, and to try the adjustable rings but they would inspect my scope if I really wanted and it would take 6-8 weeks, because, well, Covid.

Yes it is. I missed that. I blame age.

Nikonuser, I checked for concentricity with the mirror and could not recognize abnormal deviation.

After using sigfreund's reticle centering advice, I used a laser bore sighter and trial/error.

Ended up with =5/-5 elevation inserts on the rear and -10/+10 inserts for windage on the front. The rings are 4.75" center to center on the rail.

It was end of day, so I wasn't able to try the alignment on a real target at 20 yards yet. We'll see.

Thanks for the help, guys.