Adjustable scope rings: an installation how-to

[Booger]

If I understand (and I may not) the thought is that if the scope's adjustments are used to bring the POA into line with the POI the result will be true at only one distance.  The adjustable rings are used to bring the scope tube itself into an orientation parallel with the barrel.  They compensate for a canted mount on the barrel.  With the scope tube in alignment with the barrel there is no need for adjustment of the scope itself.

The Sun rings are designed in such a way that all horizontal adjustment may be performed with the rings.  The scope adjustment need not be touched.

This way you get a true center of the scope. If you notice sometimes at 30 yards you hit to the left and when you shoot 60 yards you might hit a little to the right. With the scope centered like this you will get a true right and left at all ranges. Now you will need to use hold over. That is the way I understand it.

[nervoustrigger]

Yep, you guys pretty well nailed it.  Precision shooting with an air rifle is complicated enough without dealing with criss-crossing left/right at different ranges. 

Once I got a grasp of the problem, there's no going back to the old "put the scope on and twist the knobs" approach to sighting in a rifle.  Repeat after me:

The turrets are not for "sighting in".   The turrets are for fine tuning.

First, optically center the scope and don't touch the turrets again until the end.  Then you have a choice.  Either bend the barrel or use adjustable mounts and get the rifle shooting close to your POA.  I typically use 25 yards and adjust until it is within 1/2" (sometimes closer) of the bullseye before touching the turrets.

Optical Centering
I glazed over optical centering in my writeup so I'm going to elaborate on it here.  Firstly, the mirror method and counting clicks are better than nothing but I get the best results with a V-block.  You don't need anything fancy.  Just glue a couple of 2x4 scraps together and run it through a table saw to cut out a V.  Then hog out an intersecting channel to allow the turrets to swing through as you rotate the scope tube.

When you are ready to center your scope, clamp the V-block in a vise (or something else suitably stationary) and point the scope at a target.  I say a target...anything with a grid or pattern that you can use as visual markers is fine.

What you want to be able to do is spin the scope and have the intersection of the crosshairs to remain in the same place throughout the rotation.  The way you do that is focus on one turret at a time.   Doesn't matter which one you start with so I'll pick the windage.  Orient the scope normally and take note where on the X-axis of your target the crosshairs rest.  Then rotate the scope 180° and take note again where the crosshairs end up on the X-axis relative to the previous spot.  Now adjust the windage turret to an imagined midway point between those two spots.

Repeat this back and forth until the spot on the X-axis ends up in the same place when you rotate the scope 180°.  While you are rotating the scope back and forth, you will probably notice the crosshairs orbiting against your target.  You want to ignore that.  All you care about right now is the X-axis and where the crosshairs end up left-to-right when the scope is oriented normally versus when it's upside down (rotated 180°).  What it does in between those two points is of no interest.

Once you have the windage fine tuned, now turn your attention to the elevation turret.  Same idea except you're now focusing on the Y-axis.

When you're done, you should be able to rotate the scope 360° and the crosshairs will remain in the same spot on the paper.

Caveats
Be sure your scope's parallax (range) is set correctly or you'll drive yourself crazy trying to get the crosshairs to stop orbiting.  It's one thing to have a consistent cheek weld when you're holding a rifle, but here you have nothing to help you place your eye in exactly the same place behind the ocular bell. 

For that reason, if your scope does not have an adjustable parallax, you need to do this process at the range at which its fixed parallax is adjusted...not what it says on the spec sheet (it's a lie!) but at the range where you can bob your head and not have the crosshairs move against your target.

Closing
I need to make some improvements to the Sun guide, particularly some useful points sent to me by Thomas (Roadworthy).  Maybe the next rainy Saturday.  Meanwhile if you guys  have any suggestions, corrections, or criticisms, please let me know.

[airgunwarriors]

Just absorbed a ton of great information! My brain is tried now! Really awesome Jason!

[bjr72]

Just wanted to comment on the optical centering of the scope because I just finished doing it and and to prevent other newbies like me from chasing their tail.  Many scopes will never perfectly optically center.  There might always be some orbiting around the target while rotating the scope.  I got mine orbiting in a very small circle.... just one click either way elevation or windage would send my crosshairs on a wild goose chase.

[Pellgunfun]

Just wanted to comment on the optical centering of the scope because I just finished doing it and and to prevent other newbies like me from chasing their tail.  Many scopes will never perfectly optically center.  There might always be some orbiting around the target while rotating the scope.  I got mine orbiting in a very small circle.... just one click either way elevation or windage would send my crosshairs on a wild goose chase.

That's very true.  It has to do with the distance the crosshairs travel between each click.  Since there is not really a way to adjust "in between" the clicks, it's just something we have to live with.  If your scope is say a (1/2) .5 inch per click you will have a larger "orbiting zone" than a scope that has (1/4) .25 inches per click or smaller.  The smaller the distance in between clicks, the smaller the "orbiting zone" will be. 

[nervoustrigger]

Imperfections in the scope tube will also do it, such as having been squeezed out of round by overtightening the rings.

[nervoustrigger]

For anyone interested in how well the Sun adjustable rings hold a zero, in late June I sighted in my QB78 at 43 yards, managing to need only four clicks of windage from the BSA 6-24x44 and no clicks on the elevation.  The sighting session ended with a housefly leaving an indelible mark on the target paper:



Nevermind that I probably couldn't duplicate that shot one in ten times, it was pretty freaking sweet.

Today, after two months of daily handling and use, my wife bumping the rifle standing behind the door from time to time, and so forth...I was beginning to have some doubts that the rifle was properly zeroed.   So I hung up a target at 65 yards over on my neighbor's property (mine is limited to about 45 yards).  Winds were non-existent so it looked like all I needed to do was compensate for drop:  two dots of holdover at 16x mag.  No joke, after two shots I said that's good enough for me!

[Laz]

For anyone interested in how well the Sun adjustable rings hold a zero, in late June I sighted in my QB78 at 43 yards, managing to need only four clicks of windage from the BSA 6-24x44 and no clicks on the elevation.  The sighting session ended with a housefly leaving an indelible mark on the target paper:



Nevermind that I probably couldn't duplicate that shot one in ten times, it was pretty freaking sweet.

Today, after two months of daily handling and use, my wife bumping the rifle standing behind the door from time to time, and so forth...I was beginning to have some doubts that the rifle was properly zeroed.   So I hung up a target at 65 yards over on my neighbor's property (mine is limited to about 45 yards).  Winds were non-existent so it looked like all I needed to do was compensate for drop:  two dots of holdover at 16x mag.  No joke, after two shots I said that's good enough for me!

That's great news. I just got a pair of 30mm Sun Optics adjustable rings for my Condor/SideWinder. My current issue is obviously using too much elevation clicks Up to zero it, and too much for comfort on the windage. The Side Winder gives me about 252 clicks elevation. But zeroed, I only have about 49 clicks Up. Not good for long range.

Optically centered, I would get a solid 126 clicks Up or Down.Which I hope to get close to with the rings.

Your guide is very informative. Thanks for taking the time to do it!

[K_sqrd]

Great job on the write-up and thanks for taking the time to do it. Having been down this road before, I do have a suggestion for the users.
When adjusting for elevation, instead of rotating the rear scope ring, as indicated in your instructions, simply remove the two screws which
hold the base to the rail, pick the scope straight up with attached rings and rotate the rear pin in exact increments of 1/2 or one full turn. Return
the scope to the base, carefully aligning the base screws with the holes in the pins and tighten them up. Take a few more shots and check
your POI. Then repeat as necessary.

The advantages to this are :
> you only have to deal with putting your scope rings on once
> the elevation and windage adjustments are now totally independent - rotating the rings can change the POI for windage whereas rotating
   the pin alone does not.

One other thing to try is to make note of where your first and second POI holes are and measure the distance between them. That distance
will correspond to the number of turns of the pin. As an example if one full turn (360 degrees) of the pin makes a change in POI of X inches
at Y distance, you now have a ballpark idea of how many turns or half turns it takes to get you near your chosen POA / POI.

HTH

[Laz]

  Just an update. I stripped a windage set screw. Rings are totally useless now, won't tighten down. Going to do it right and get Sportsmatch adjustable rings.

[nervoustrigger]

Ah, sorry to hear that. 

I've used these type rings about a dozen times and I did manage to strip a windage screw once.  It was a perfect storm of variables all the wrong direction:

• too little thread engagement - Was using a lot of windage adjustment and the set screw was buried pretty deep on one side such that there was very little thread engagement left (i.e. most of the set screw was reaching out into open space to pinch the gimbal.  If I'm in that situation again, I will replace the set screw with a longer one.
• residual threadlocker - The set screw was pretty hard to turn so I could not tell when it became tight
• too much torque - Was using the long side of the hex key to tighten the set screw.  Had I been using the short side, I would have had a better feel for when to stop torquing.

Thankfully it wasn't a big deal for me to drill and tap to the next size up and I was back in business.  Do you have the tools to do that?  If instead you're just planning on tossing them, let me know which P/N and I may be interested in paying shipping and a few bucks for your trouble.

[Laz]

Ah, sorry to hear that. 

I've used these type rings about a dozen times and I did manage to strip a windage screw once.  It was a perfect storm of variables all the wrong direction:

• too little thread engagement - Was using a lot of windage adjustment and the set screw was buried pretty deep on one side such that there was very little thread engagement left (i.e. most of the set screw was reaching out into open space to pinch the gimbal.  If I'm in that situation again, I will replace the set screw with a longer one.
• residual threadlocker - The set screw was pretty hard to turn so I could not tell when it became tight
• too much torque - Was using the long side of the hex key to tighten the set screw.  Had I been using the short side, I would have had a better feel for when to stop torquing.

Thankfully it wasn't a big deal for me to drill and tap to the next size up and I was back in business.  Do you have the tools to do that?  If instead you're just planning on tossing them, let me know which P/N and I may be interested in paying shipping and a few bucks for your trouble.

Yeah, in excitement while trying to set them up, I left a jam screw tightened in whilst trying to adjust a windage 

I don't know the P/N? I have the 30mm SM0130 ones.

[Tater]

Sorry to hear that happened Laz.

[Laz]

Sorry to hear that happened Laz.

Thanks Jerry. Was completely my fault, as these rings do wonders for people use them properly. So I put an order in for some FX No Limits rings. Sacrificed windage adjustment, but it is cranking the elevation that concerned me more. If push comes to shove though, I'll get some Sportsmatch fully adjustable rings.