lapping scope rings

kripton

Well-Known Member
I have just fitted a Kahles 8x50 illuminated scope to my Shultz and Larsen Victory rifle using Shultz and Larsen's own specially made rings incorporating the bases which fit the dovetails built into the top of the action.

I have not fully tightened up the top of the rings as I noticed that with the scope sitting on the bottom of the rings, as I fitted the top of the rear ring, the front of the scope lifted slightly off the front ring.

I have checked that the scope tube is not distorted by turning it upside down when it still lifts off the front ring as I start to tighten the rear ring.

I suspect that the only solution is to lap the rings which is where I need help please - First does anyone have another diagnosis for the problem and if my diagnosis is correct, will lapping the rings solve it?

If I lap the rings (the scope has a standard "one inch" tube) what do I use for the lapping tool and what lapping paste is recommended?

Thanks in anticipation guys.

Keith
 
I've never done it. Ever. I have a feeling that it's just a vehicle to sell lapping kits.

BUT what I do do is use a 1" steel rod, about ten inches long, to set up and align the rings before I offer the 'scope to them. And with the generic Redfield turn in type this is important when first turning in that front ring until it beds. If you've not a 1" metal rod then a broom stale will do for that or any HANDLE on a sturdy screwdriver.

Last tighten the rings down like you'd tighten wheel nuts on a car. Work on an X pattern and tighten if it has double screws the inside ones then the outside ones. Always gradually, in an X, a little at a time and evenly. So top left then bottom right, then bottom left followed by top right and so on

Don't tighten one screw all the way, then the next, then the next. I use a set of feeler gauges to check I've an even clamping down happening measurig the gaps between the rings at each screw so they close evenly by the same amount. So screw down all sides to 50 thou, 40 thou, then to 30 thou then to 25 thou then to 20 thou...if it will go that far.
 
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Thanks for the advice guys.
I have emailed Alan Rhone (who imports Shultz and Larsen) as the rings are sold as "one inch" rings and I have measured the scope tube at 25.83 mm. I await his reply but it occurs to me that when fitting the rings to the action the instructions suggest that you squeeze together the top of the bottom ring which will open up the base"claw" of the ring and make it easier to slide onto the dovetail on the action.- i.e.they are slightly sprung. Perhaps therefore I am worrying about nothing and the rings are designed to spring slightly apart to accommodate the scope tube when the top of the rings are tightened down.
 
KR, I'd contact Kahles and they'll tell you if your 'scope is 1" or 26mm".

If it is 26mm then, from my experience, you'll not be able to "lap" out enough. The answer would be to have the rings milled out. But then you may find that there is not enough metal left in them.

This suggestion of bending, nipping, tweaking is all to be avoided. For whatever and however you adjust to the sides of the ring the dimension from top to bottom can't ever be more than 1" can it? Indeed if you expand the sides to increase that distance you merely decrease that 1" from top to bottom.

You need correct rings and not a cobble job. Now a 1" tube in 26mm rings can and will work. Some use Araldite (OUCH) or others use electrical tape (NOT AN AT ALL BAD IDEA FWIW) but for a 26mm 'scope in a 1" ring you must hone. Lapping won't do it.

Hope you get it sorted.
 
they are 1" tubes

if the scope rings are not parallel to the receiver and cause the scope to lift I would suggest that lapping will only serve to reduce the viable clamping area as they sound well out of alignment

I assume its these is it:?

sl-mounts-36-m-01.jpg


not my personal choice of designs.

They shouldn't be under tension front to back
 
Just measured my old Kahles 8x56, about 30 years old, and it is 26mm, if that's anything to go by.
 
Thanks JTO. Perhaps my calipers are inaccurate as looking at the "blurb" by Kahles which came with the scope, the tube diameter is apparently 25.4 mm/one inch. The "blurb" also gives the same measurement for the 8x56 version but I do not know the date of printing - perhaps your 8x56 was an earlier edition.
 
I have a Schultz and Whatsit Victory and the same rings (albeit 30mm) and mine are fine, everything lines up as it should, there is no lifting or twisting, minimum force is needed to tighten them up (2NM). With the scope fitted it is easy to loosen the base clamp-screw and remove the scope which refits into either of the two positions on the action with less than 1cm change in POI @ 100M.

It sounds like something is wrong somewhere, lapping is for correcting differences of a 'few' thou not hundreds. Ask for another pair.

If you still can't get it right I have a +20MOA S&L Picatinny rail which was fitted to my rifle, new (by Steve Beaty at Ivythorn), which I removed the day after it arrived (because it was 20MOA and when I moved the scope from my other rifle, the POI was miles off) - yours for £45 delivered
 
I had some delrin material machined to 30mm outside and 26mm inside diameters to cut off as spacers for any 26mm scopes by fitting to 30mm ring sets but have not needed to use it it yet.
Martin
 
Thanks JTO. ........perhaps your 8x56 was an earlier edition.
It certainly is! About 1981 vintage.

Before you butcher your rings, have a look at Burris XTR Signature Rings. They have several sets of softish inserts to move/adjust the scope alignment.
 
Personally I lap all my scope rings but it corrects tiny differences not large gaps i.e. You can see it lift.

Are tightening down in an X pattern or just one ring at a time?
 
All rings lapped here to, never marked a scope since starting to do it.
No fancy kit just a 330mm length on 1 inch silver steel and some fine valve lapping paste.
Total expense less than £20 and will last a lifetime.

Neil.
 
Some rings have a small soft pad top and bottom that allow the scope to move within them but not mark it. Optilocks would be the ultimate option if they fit your dovetails, but I think their might be others that are similar.
 
Apart from optilock type most mounts are not 100% aligned. I just wax the mount, wax the scope and use an aluminium filled epoxy in the mounts, get the scope in the right position and tighten the screws to a fraction of the normal torque. Let the resin set over night and then torque the rings properly. I always use one piece rails and the mounts can stay on the scope even when going on a different rifle.
Another advantage of this method is that one can fix slight height differences between the mounts by putting one or more narrow strips of electric tape in one mount before epoxy. Possibly up to 10 moa.
edi
 
I have Schultz and Larsen rings in both 30mm and 1inch, I find that if the rings are not tightened on to my action they won't accept my scope tube. But when they are on the rifle my scopes drop straight in, make sure you never tighten the screw on the bottom of the ring without it being fitted to the rifle as you could crack them and also that the bolt heads face to the right.
 
Thanks to all who responded - it is great to see the breadth of expertise on this forum.
I received an explanation from Alan Rhone which (in annotated form) advised ; -

1. The S&L slide and lock rings are made from spring steel and will never be exactly the same as each other.

2. Some contraction is normal.

3. The rings will spread to fit the scope (otherwise a one inch scope would not sit properly in one inch rings)

I have followed his advice to stick masking tape inside the rings to prevent marking the scope and (although I have yet to test fire with the scope now on the rifle) all seems to be well and solid.

2.
 
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