Rifle Scopes Sanding/aligning scope mounts

[Zatoichi66]

Back in the 1970s, my father & his shooting buddies had a “gizmo” that was a true steel rod with a 90degree handle in the middle. It looked like a “T” with en extremely short stem.

After they installed scope mounts, they used 600 or 800 grit sand paper to polish the mounts & ensure they were true & didn’t effect the scope.

I’ve never seen it since & never used this practice on my Leupolds & factory mounts.

Is this practice to align scope rings still recommended for precision rifles, or gas CNC & modern tech rendered it obsolete?

Thank you.

 

[Trigger Monkey]

It's called lapping, normally you would use a fine lapping compound instead of sandpaper but in my opinion it's a outdated process for precision rifles. There may be some cheap two piece ring and base combos that could benefit from it but outside of that there's the potential that you could do more harm than good. I lapped one set of cheap Weaver rings and that was enough for me to never want to do it again.

 

[Nik H]

No longer necessary if you buy high quality rings....an artifact from the dark ages IMHO

 

[Zatoichi66]

I’m pushing 60 & this is my first soirée into precision rifles. I thought I’d ask before doing something I regret—like destroying perfectly good mounts.

 

[John boy jh]

No longer necessary if you buy high quality rings....an artifact from the dark ages IMHO

Just out of curiosity I lapped a pair of Night Fource rings to see how true they were. They were close but not perfect. It could have been my tail was not perfectly flat

No longer necessary if you buy high quality rings....an artifact from the dark ages IMHO[/QUOT.

 

[Zatoichi66]

Thank you for your education & help.

 

[John boy jh]

Just out of curiosity I lapped a pair of Night Fource rings to see how true they were. They were close but not perfect. It could have been my rail was not perfectly flat[. In that case it would be beneficial to lap them on the rail and on the gun. IMHO

 

[Nik H]

Just out of curiosity I lapped a pair of Night Fource rings to see how true they were. They were close but not perfect. It could have been my tail was not perfectly flat

Could be. I have used NF X-Treme Duty, ARC M10 and Spuhr. Never lapped any of them and always run Tall target tests over 10-15 mil of elevation change. Never seen an error that wasn't within expected values.

 

[just browsing]

Lapping rings = destroying rings. Modern mounts are machined to tighter tolerances than what lapping bars are able to provide.

 

[Trigger Monkey]

These are a set of NF rings just torqued onto a factory Mossberg scope base, I think it's EGW with a set of alignment bars mounted up, no lapping needed.

 

[fdkay]

I think that some of the need was really caused by the actions themselves.
My Dad had a Rem long action that would literally bend a one piece mount.
The real answer is to bed the mounts.

 

[Trigger Monkey]

The real answer is to bed the mounts.

I've experienced that too and have bedded scope bases for three Remington rifles and even one for my Bergara just to be safe.

 

[mj30wilson]

I think it really depends on the style of ring also. Leupold still makes a dovetail lock ring that sometimes benefits from lapping to get true alignment.

 

[RichardSmithe]

Is it easy to ruin these? Should i just give it to the professionals?

 

[Dthomas3523]

Is it easy to ruin these? Should i just give it to the professionals?

.......please elaborate your question. This post is a bit suspect.

 

[Newbie2020]

...crickets....hmmmmmmm....

 

[308pirate]

Lapping rings = destroying rings. Modern mounts are machined to tighter tolerances than what lapping bars are able to provide.

How do you know any of this? Do you have any inspection numbers to validate your claim? Or are you just repeating what you've read on the internet?

Have you ever seen a dimensional blueprint for MIL-STD-1913 rails? I have. And I know how to interpret it. There is no way, even if a machinist used half the linear and geometric tolerances given to him, that the alignment between the front and rear ring would be perfect.

Just because something is good enough doesn't mean it can't be improved. You just have to know how.

 

[308pirate]

These are a set of NF rings just torqued onto a factory Mossberg scope base, I think it's EGW with a set of alignment bars mounted up, no lapping needed.

Is your setup good enough? Most likely it is.

Can that alignment be better? I'll put money on it. That alignment tool is a rough visual gage. You have no idea if the tips are .0001" off or .001" off.

 

[Dthomas3523]

Smith’s like Borden will lap them down enough to use bedding to let the scope sit as perfectly and stress free as possible.

You have many things going on here. You have the receiver, sometimes rail if it’s not integral, then you have the rings/mount, and finally the scope.

Sure, each individual piece is machined very well. But they weren’t matching specifically with the other parts. So, there can be some stacking tolerances.

I don’t do anything to my rings. But if you want to absolutely ensure the optic is sitting as stress free as possible, you can cut them down and bed them.

Same scenario with bedding a chassis. Does it need it? For most people, no.

 

[Dthomas3523]

That being said, I would never just lap them and sit the optic in them. Either lap them down enough to bed the optic, or don’t touch them.

 

[just browsing]

How do you know any of this? Do you have any inspection numbers to validate your claim? Or are you just repeating what you've read on the internet?

Have you ever seen a dimensional blueprint for MIL-STD-1913 rails? I have. And I know how to interpret it. There is no way, even if a machinist used half the linear and geometric tolerances given to him, that the alignment between the front and rear ring would be perfect.

Just because something is good enough doesn't mean it can't be improved. You just have to know how.

2 years in the making eh?

That’s fair though, point taken. Most things could probably be improved with the right knowledge and equipment.

But the fact of the matter is that the VAST majority of people reading this need to stay the fuck away from a lapping bar.

If you believe the benefits of lapping rings outweigh the disadvantages, you have the wherewithal to properly lap rings, and you can shoot the difference on top of it... knock yourself out. The other 99% of people are still better off destroying them.

 

[RichardSmithe]

I meant, should I try doing this myself or is it better to let it to someone who knows what they're doing. I am really not that skilled in sanding and I have tried to get better, trust me. The thing is that I just do not know how to do it properly. A friend told me to get a sander like this one as it was supposed to become easier. I got one and I tried it out. It is true, there is some difference. It makes the job easier, but that is just practice. Thank you for all of your advices and responses, I will probably find someone that has more skill than me

 

[gnochi]

I meant, should I try doing this myself or is it better to let it to someone who knows what they're doing.

1. It is easy to ruin rings by trying to lap them.

2. There is zero reason for anyone on this planet to lap scope rings for anything made since ~1970. Scope tubes, rings, mounts, etc. all have inherent ability to flex a bit and carry loads without damaging the material. In fact, you cannot carry any load - including the friction you need to prevent the scope from slipping upon recoil - without flexing. True “stress-free” scope mounting is physically impossible. What you can get is a microscopic reduction in how much bias there is in the rings flex around the scope and the scope flexes within the rings, but that has a grand total of “no environment/ shooter/ scope/ rifle/ ammo system on the planet is consistent enough for this to make a statistical difference in performance” impact.

3. If you are for some reason extremely concerned about a scope that’s more durable than tissue paper, just get the Burris Signature rings, which are perfectly secure for anything shy of tossing a rifle out of a plane at 5000ft onto concrete, and have a spherical bearing system that is inherently superior to any lapping anyone on the planet says they can do.