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Rifle Scopes Ring lapping question

huntfish

Sergeant
Full Member
Minuteman
Feb 16, 2010
166
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In an effort to show my ignorance, I ask the following...

I use lots of Warne rings and Talley rings and I have never lapped them. Warne instructions suggest that you not lap and I am not sure about Talley. I have never had trouble with ring marks or scope movement either. This has been true of rifles up to 338 Edge and 375 H&H. But my question is really a physics question, I suppose. I don't deny that lapping can eliminate ring marks, for the record.... but

When you lap rings, I understand that you increase the surface area of scope ring that comes in contact with the rifle scope, hence, in theory, increasing the ability of the ring to "hold on to" the tube of the scope. But does spreading out the compression actually decrease the liklihood of slippage, as the total compression to the scope is actually not increased, only dispersed? Regardless of the footprint of the ring on the tube, the total force exerted on the scope tube can only be increased by tightening the rings. What am I missing? There has to be something more as everybody seems to do it.
 
Re: Ring lapping question

Its not an issue of more contact but having the saddle of both rings in perfect allignment. This it to avoid torque on the scope tube.
 
Re: Ring lapping question

Is it absolutely neccesary--I doubt it. Especially with higher end rings, but I do it just to eliminate one more of those variables that would make me doubt myself. I will say this, with my badger ordnance rings and nightforce rings (thats all I have), when I lap them, you can see the misalignment thru where the lapping bar removes metal. BTW, I use Sinclair's lapping kit which is very nice.
 
Re: Ring lapping question

CCooper what scopes do you have on the NF rings?

Id be interested to see what actually happens when you lap NF rings because according to them their rings should not be lapped.

Not disrespecting or anything, just thought it would be interesting
smile.gif
 
Re: Ring lapping question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Matthew Lundy</div><div class="ubbcode-body">Its not an issue of more contact but having the saddle of both rings in perfect allignment. This it to avoid torque on the scope tube. </div></div>

I lapped with bars and fine lapping compound for years. The last 10 or 12 years I have been bedding them. Use the same aluminum or steel bar that you lap with. Just put a couple of coats of some kind of release agent. Lately when I don't have DevCon Aluminum I have substituted with J-B Weld and have had VERY good results.

Good luck.
 
Re: Ring lapping question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: huntfish</div><div class="ubbcode-body">... But does spreading out the compression actually decrease the liklihood of slippage, as the total compression to the scope is actually not increased, only dispersed? Regardless of the footprint of the ring on the tube, the total force exerted on the scope tube can only be increased by tightening the rings. What am I missing? There has to be something more as everybody seems to do it.

</div></div>
It does not decrease slippage, as you pointed out the force is the same.

What changes is the pressure, which is force <span style="text-decoration: underline">per unit of area.</span> The force is the same, the area of contact is what changes. And actually that is assuming that the rings don't fully contact the scope body before lapping.

The pressure decreases, as the area of contact increases, keeping the total force on the tube the same.
 
Re: Ring lapping question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MeridianNW</div><div class="ubbcode-body">
The pressure decreases, as the area of contact increases, keeping the total force on the tube the same.

</div></div>

hmmm, isn't pressure what ultimately holds the scope in place? in that case, lapped rings should hold the scope less effectively?
 
Re: Ring lapping question

Good high end rings do not need to be lapped.When you have a high end scope chances are the tube was CNC machined.This is where top rings and scopes separate themselves from the rest.Ohh and yor base or rail is also true.
 
Re: Ring lapping question

Think of it this way:

When do you personally have more traction? When you are standing squarly on the ground, or when you are standing on your tiptoes.

Force would be equal, but tiptoes exerts more PSI on the ground, but I sure wouldnt try to take off at a run on my tiptoes.... fall flat on my face.
 
Re: Ring lapping question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: vman</div><div class="ubbcode-body">CCooper what scopes do you have on the NF rings?

Id be interested to see what actually happens when you lap NF rings because according to them their rings should not be lapped.

Not disrespecting or anything, just thought it would be interesting
smile.gif
</div></div>

vman, I have a Nightforce benchrest in the Nightforce rings. I think they say to not lap their ultralight rings, but don't think they say for the steel rings. BTW, I have the steel rings. No disrespect taken.
 
Re: Ring lapping question

The rings are rarely the problem, but rather the receiver inaccuracies that cause the misalignment that folks choose to solve by lapping.

Rings and bases by their very nature are easier to maintain tight tolerance on during the manufacturing process than what is normally seen in their receiver counterpart.

Most receivers after being in some cases, crudely machined, are hand-finished on a buffing wheel or sander and the dimensions can be all over the place. Winchesters were notorious for this and most Remington 700s that you'll take out of the stock will show the witness line of just such grinding hidden below the stock line. This is where a lot of the misalignment is originally contrived.

With all that said, lapping can be an effective method for righting the wrongs so to speak, but not the only solution.
 
Re: Ring lapping question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: MeridianNW</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: huntfish</div><div class="ubbcode-body">... But does spreading out the compression actually decrease the liklihood of slippage, as the total compression to the scope is actually not increased, only dispersed? Regardless of the footprint of the ring on the tube, the total force exerted on the scope tube can only be increased by tightening the rings. What am I missing? There has to be something more as everybody seems to do it.

</div></div>
It does not decrease slippage, as you pointed out the force is the same.

What changes is the pressure, which is force <span style="text-decoration: underline">per unit of area.</span> The force is the same, the area of contact is what changes. And actually that is assuming that the rings don't fully contact the scope body before lapping.

The pressure decreases, as the area of contact increases, keeping the total force on the tube the same.


</div></div>

According to Badger, their 1" wide rings have more holding power. They claim more surface area equals more holding power:

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BadgerOrdnance Website</div><div class="ubbcode-body">The MAX-50 Rings are ONE inch wide, giving them 60% more holding power than any other ring available. Utilizing 6 #8-40 Torx screws to distribute the load providing the maximum amount of holding power while minimizing the chance of damaging the scope. Machined from steel as “Matched Pairs” and serialized. Mil-Std-1913 compatible (Picatinny optic mount) designed for the demanding .50 BMG round.</div></div>
 
Re: Ring lapping question

More surface area does equal better holding power, but that surface area is easily obtained by having the entire ring making contact.
If you have a ring that is twice as large as another, yet it makes less than half the potential contact it should; the ring with less initial surface area, making 100% contact is going to come out the winner.
That is not to say that Badger's rings aren't making good contact, but shear size alone will not necessarily win the race.