Is Scope Lapping necessary?

oldfortyfiveauto said:

That is correct, however when the are installed correctly the two rings are not concentric. One ring will be slightly lower than the other.

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Not on any I’ve installed.

And now we’ve come full circle...

Varminterror said:

In 30 some 77 MkII’s and Hawkeyes I have owned, and dozens more I have serviced in my shop, this has not been my experience.

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Next time you get a ruger in to mount set the action up on your surface plate and get your height gauge and indicators out. You won’t like what you find.

Good thread. The original question was, in effect, "Is lapping scope rings necessary?" In summary, aligned rings with maximized scope/ring mating surfaces are necessary. Lapping is one way to get rings aligned and mated. Better quality rings and mounts (e.g., Badger), self-aligning ring inserts (Burris), shims, and well-manufactured unitary mounts with integral rings (e.g., DNZ) are other means to the same end. The point is that lapping is a means, not an end. So no, lapping is not always necessary, but it can often be helpful.

Aim1 said:

Anyone never lap and never have a problem?

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Warne and American Defense one piece mounts.

I started lapping rings as I upgraded to better scopes. I was amazed at how little contact there was on some of them. Lapping tools are cheap compared to the price of a good scope. I've seen scopes damaged by miss aligned rings. hdbiker

Varminterror said:

Checking alignment with the pointed spindles doesn’t tell you anything about the ring contact, only where the average boreline is pointed. If they don’t line up, I shim my bases, or replace them, to gain alignment.

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I've never mounted a scope. Question. Review of post #23 might be obvious but to correct any and all misaligned rings use shims? Are there other methods of achieving alignment? Should the individual mounting scopes have an assortment of shims at the ready? If so what is a good assortment to have? I ask because I'm thinking about venturing into this activity and have really no idea how it's done other than watching a few you tubes.

As an overall observation it seem logical to use the proper tools to mount scopes, levels, lapping and torque wrenches as this would put the least amount of stress on the scope and assure proper alignment with respect to the bore. Thanks brother.

I’m answering via mobile, so I don’t see the post numbers - not sure which is #23 without counting...

But to your question - “should the installer have shins on hand?”

My personal answer:

Yes, I do. I own various thicknesses of shimstock for various uses, so I always have some on hand. For one piece mounts, a guy can get away with simply bedding the bases, without shims (bedding acts as the shim), but for two piece bases, I typically use a shim, then skim bed once my shim height is determined, just to hold everything together.

I will also say this:

The volume of lapping vs. not lapping threads kicking back and forth online makes the process seem exceedingly onerous to confirm and, if needed, correct alignment and contact. Other than waiting for bedding compound to set and cure, I can’t say I’ve felt like I spent “too much” or even “very much” time in lapping and bedding bases and rings. It’s a very quick job with very low cost tools and materials. I’m sitting here with a $2500 Nightforce ATACR on my bench, sure seems to make plain sense to avoid potential damage by spending 15min with a $30 tool set to ensure alignment and contact of my $200 rings to protect my $2500 optic...

Alignment and contact are independent aspects of the task. Rings can be perfectly aligned, but only have 25% contact. Bedding and shimming bases corrects alignment, lapping should only correct contact.

I think the fact that some do and some don’t while achieving great results pretty much proves it is not always necessary.

I’ll take that one step further and say there are far more scopes out there mounted in unlapped rings than there are in lapped ones.

I wonder what Laplanders do?

Maybe the stuff I buy is spot on..............never any problems. That`s going back over 50 years.
Maybe some the problem is more self made than machine made. J s/n.

Aim1 said:

I thought Leupold made good rings?

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Yep. Leupold is less than forthcoming about the country of origin of their scope components and their rings. Some of the Leupold rings are made in China: They are no better than other cheap rings.

i always check ring alignment and lap. A friend brought me a rifle someone had scoped for him. The $2,300 scope was ruined by out of alignment Leupold rings.

@Walkalong - I think it happens more than a guy might think it would. I blame it on this: Some unwitting newbie hears an S&B or Nightforce is the best scope out there, above their budget a little maybe, and they “know” Leupold makes great rings, since they have such a grand old reputation, so they try to balance some of their overspend by saving money on “good” Leupold rings.

Not picking on Leupold really, but I know a lot of guys expect way too much of their rings and bases because they assume the same reputable quality as their optics... of course, that optic quality is among a fleet of hunters who don’t ask much from their optics, so it’s largely inflated as well, but hey, guys swear by their gold rings...

Walkalong said:

So he spent $2300 on a scope and $30 on rings?

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NO. He spent $60 on Leupold quick release rings allegedly made in the USA.

Finally got another Ruger in to mount a scope on. This one is a 77/17WSM. An can be seen holding the scale on center to the bottom of the front ring there is a significant gap under the rear ring. You're not going to lap that out. What I do is snug up the rings with the cross bolt lightly snugged up, then work my way up to the proper torque. This seems to cause the least amount of issues with the scope.

oldfortyfiveauto said:

Finally got another Ruger in to mount a scope on. This one is a 77/17WSM. An can be seen holding the scale on center to the bottom of the front ring there is a significant gap under the rear ring. You're not going to lap that out. What I do is snug up the rings with the cross bolt lightly snugged up, then work my way up to the proper torque. This seems to cause the least amount of issues with the scope.

View attachment 796811

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If I'm seeing that photo correctly, there's undoubtedly something wrong there. There's no way Ruger or any manufacturer would recommend staggered height rings be used on their guns. And I'd never even think about mounting a scope in a setup like that....

Just a quick measure of the photo and comparing the spacing below the round dot in the ring mount as a % of overall height, it looks like they aren't the same height -- as if the one on the rear belongs on the front, and visa-versa. Could that be?

The 77/17’s use the same front and rear.

oldfortyfiveauto said:

The 77/17’s use the same front and rear.

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Strange. The one in the photo there sure looks (and sounds, based upon your description) like it needs different height rings like some of the other M77s do. Good luck with it.

Sorry but they are supposed to be the same.