lapping rings

7/29/2019 Lapping Rings

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Sniper’s Paradise

Kokopelli Accurizing Kit Review.

By V. Nylin (Usngunner)

A while back the topic of 35mm lapping bars, and sources for the same were being

discussed. Mr. John Werre of Kokopelli Products and I became engaged in aconversation regarding his Accurizing Kit and the need for it vice just getting a steel or

brass 35mm bar, lapping the rings and calling it good.

Quite frankly, I didn’t think I needed an entire kit and thought that it was overkill. After

some pm’s back and forth, Mr. Werre offered to provide us a kit to try and evaluate for

the site. I choose a 35mm kit as most of the staff have a 35mm scope. As the timingworked out I was the fortunate one to test the kit. My choice of words will become clear

as you read on.

The Hardware.

The kit arrived packed in a fitted case with the 35mm lap, removable handle for the lap,

two precision scope bars, lapping compound, a drill rod to use for bore alignment and

detailed illustrated instructions. (See Figure 1)

Figure 1



The idea is to use the scope bars to verify the axial alignment of the rings, the drill rodslides in the forward scope bar to assist in aligning the mount and rings to the bore.



Putting the kit to use.

When I got the kit I sat down, read the instructions and followed them step by step. Thetiming was good as I had just received my new IOR 3-18x42 Flea Scope and was ready

to mount it and go.

As I already had the base installed and rings mounted, I went ahead and placed the scopebars in the rings to see where I was.

This was enlightening. As you can see in figure 2, I had a serious vertical misalignmentbetween my front and rear rings.

Figure 2

As close as I could measure the offset, it was just shy of .040”. After regaining my

composure, running through my saltier vocabulary, and calming down a bit I started

investigating for the cause of the misalignment.

I removed the rings and base and checked them for straight and true on a granite table.

All the components were correctly dimensioned, and verified to be straight and true. Justto make sure, I took them to one of my customers Quality Control Labs and had them

verify the same with their laser inspection and dimensioning system. They had the same

results and were actually quite impressed with the tolerances of the TPS system (that is adifferent article though).



At this point I went back to the rifle and began checking it. By trial and error, I foundthat with the base installed and tightened down with just the rear screws, all was still

straight. However, when I tightened the front two screws of the base down, the forward

bar canted down at the junction of the scope bars.

The culprit was my receiver. After doing some research, I have found that this is not

uncommon for rifle receivers. The receivers are heat treated after the machining process,and it is not so much a question of “Is mine warped?” as it is “How much is it warped?”

I must admit, this was something I had not stopped to consider before this test. I knew I

did not want to lap that large of a cant into my rings. They would be useless after that forany other rifle should I decide to switch scopes. Not acceptable in my opinion.

But, since I knew where the problem was, it was a fairly simple and straight forward fix.I mixed up some Devcon Steel Bed and bedded the base while only securing the screws

in the rear and using electrical tape to maintain the front of the base in place with the

scope bars mounted in the rings to verify proper alignment. (See Figure 3)

Figure 3



After it cured, I tightened it all down and here is the result.

Figure 4

As figure 3 shows, the alignment is now nearly perfect. After the Devcon had set, I

colored the inside of the rings, and just ran the lapping bar a couple of times back andforth to see. I had outstanding surface contact, without having to remove any material at

all.



Conclusion and Summary.

I have to say, this has given me a whole new outlook on the whole scope mountingprocess, and what is overkill and what isn’t.

While just lapping a set of rings with a bar to get good contact will in fact work, it does

then commit those rings to that base and rifle. If you change scope sizes and go to adifferent set of rings, you have to do it all over and now you have two dedicated sets of

rings for that rifle.

It also defeats the purpose of the pictaninny system in my mind. If I were to take that

lapped set of rings and scope off of that rifle, and move it to my .300 wm and torque it

down on that base, how do I know that I’m not now bending my scope the other way andputting it in a bind? I may not see the ring marks in the lapped rings, but am I taking a

chance that I am messing up an expensive optic? It’s a danged good possibility based on

what I learned doing this test.

In my opinion, fixing the base to receiver alignment first is a much better long termoption than just lapping rings. Then I know it is square and true and it gives me the

option to move scopes from rifle to rifle as I choose to without worrying about ruining anexpensive optic. Is that not the whole concept of repeatable and standardized rails and

rings and why we pay big money for them in the first place?

I’m buying this one from Kokopelli Products, and I see the 1” and a 30mm kits finding a

home my tool box very soon.

Are they more expensive than just a lapping bar? Yes, yes they are.

Are they worth it? Yes, yes they are. Given the cost of our optics, bases and rings, thepiece of mind alone is well worth it.

Gunner

For more information on this product, please contact:

Mr. John Werre

Kokopelli Products

3820 Foothill Rd.

Kalispell, MT 59901USA

(406) 755-3220

www.kokopelliproducts.com

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