Is lapping necessary?

Rifle scopes, iron sights and optics. Spotting scopes and target acquisition devices.

Is lapping necessary?

Post by junjun » 11 Oct 2016, 6:49 pm

Waiting to receive my Vortex Viper PST 6-24 FFP scope. While searching on how to properly install the scope, I come across the term lapping. Is it really necessary? Asked the dealer where I get my scope from, they don't do it in store, they have to send it to a gunsmith to do, and it will cost me $80. Should I spend this money? Is there another other place I should go in Melbourne to get it done? Cheers.
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Re: Is lapping necessary?

Post by MR. WINCHESTER » 11 Oct 2016, 6:50 pm

Depends on your mounts and the way in which you install .....
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Re: Is lapping necessary?

Post by AusTac » 11 Oct 2016, 7:05 pm

get some burris signature zee rings, or something with some plastic/rubber inserts to eliminate the need for lapping, other wise a few of the guys here have done it diy style, and may be able to guide you
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Re: Is lapping necessary?

Post by MR. WINCHESTER » 11 Oct 2016, 7:07 pm

Which gun ?

( sorta, sometimes determines the mounts )
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Re: Is lapping necessary?

Post by junjun » 11 Oct 2016, 7:52 pm

It's a Remington 700 with AB Arms chassis. Great looking rifle in my eyes.
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Re: Is lapping necessary?

Post by bladeracer » 12 Oct 2016, 5:12 am

junjun wrote:Waiting to receive my Vortex Viper PST 6-24 FFP scope. While searching on how to properly install the scope, I come across the term lapping. Is it really necessary? Asked the dealer where I get my scope from, they don't do it in store, they have to send it to a gunsmith to do, and it will cost me $80. Should I spend this money? Is there another other place I should go in Melbourne to get it done? Cheers.



I've never bothered, but I don't spend much more than $300 on my scopes.
I prefer a one-piece pic rail and separate rings for their adaptability, but for a more expensive scope I would use a one-piece mount with integral rings.
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Re: Is lapping necessary?

Post by brett1868 » 12 Oct 2016, 8:20 am

What calibre is the rifle?, how much does it weigh? Tube diameter of scope? weight of scope? brand and width of rings?

A light rifle in a large calibre will recoil more than a heavier rifle in the same calibre, simple physics. As the rifle recoils the inertia needs is transferred to the scope via its contact patch with the rings. It's entirely possible for scopes to "slip" in the rings under recoil if there's insufficient surface contact or tension between rings and tube. The purpose of lapping is to increase the surface contact area between the tube and rings to prevent movement as well as align the rings concentrically it improve accuracy. That's the logic behind lapping covered but if it's actually required in your case will depend on the answers to the questions above.
Alternatively, lapping is generally a good thing and $80 isn't too much money to have the scope lapped and mounted. I spent a couple hundred and bought a full kit from the U.S that covers 1", 30mm & 34mm tubes.
Old timers and myself included used to line the rings with sticky tape which acted as a filler for improving surface contact area.
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Re: Is lapping necessary?

Post by pomemax » 12 Oct 2016, 10:48 am

Do not lap your rings in wait until you have turned a set of rings over puts a real bad divot into the bottom of your scope if it not totally split and wrecked have one like that i only payed 1500 for it . After that you will spend some cash get a lapping kit and never had it happen again i cover all my rings on the bottom only with cloth electrical tape after lapping .Just make sure its flat in the rings
http://www.ebay.com.au/itm/Wheeler-Scop ... Swq5pXPiFx
this set you even get a torque wrench
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Re: Is lapping necessary?

Post by brett1868 » 12 Oct 2016, 11:08 am

pomemax wrote:Do not lap your rings in wait until you have turned a set of rings over puts a real bad divot into the bottom of your scope if it not totally split and wrecked have one like that i only payed 1500 for it . After that you will spend some cash get a lapping kit and never had it happen again i cover all my rings on the bottom only with cloth electrical tape after lapping .Just make sure its flat in the rings
http://www.ebay.com.au/itm/Wheeler-Scop ... Swq5pXPiFx
this set you even get a torque wrench


That be the exact kit I got + I ordered the 34mm bar as well. I don't like the compound they supply so I got some valve lapping paste in a finer grit and do both the top and bottom at the same time. Rather then by hand as Larry demonstrates below, there's a flex drive in the kit allows you to use a cordless drill which vastly speeds up the process. Care must be taken to ensure that too much materiel is not removed or you'll stuff the rings.

Let Larry guide and inform you :)
https://www.youtube.com/watch?v=fTIY9cZlpPs
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Re: Is lapping necessary?

Post by junjun » 12 Oct 2016, 8:52 pm

brett1868 wrote:What calibre is the rifle?, how much does it weigh? Tube diameter of scope? weight of scope? brand and width of rings?

A light rifle in a large calibre will recoil more than a heavier rifle in the same calibre, simple physics. As the rifle recoils the inertia needs is transferred to the scope via its contact patch with the rings. It's entirely possible for scopes to "slip" in the rings under recoil if there's insufficient surface contact or tension between rings and tube. The purpose of lapping is to increase the surface contact area between the tube and rings to prevent movement as well as align the rings concentrically it improve accuracy. That's the logic behind lapping covered but if it's actually required in your case will depend on the answers to the questions above.
Alternatively, lapping is generally a good thing and $80 isn't too much money to have the scope lapped and mounted. I spent a couple hundred and bought a full kit from the U.S that covers 1", 30mm & 34mm tubes.
Old timers and myself included used to line the rings with sticky tape which acted as a filler for improving surface contact area.


It's a 308. I have swapped the factory stock with an AB ARMS chassis, so it's heavy. I also have a muzzle break on it, so I doubt the recoil will be too big. I might just get the kit myself and do it, since I am very sure this will not be my last rifle.

For 200 I get my kit and a wrench, sounds a good deal.
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Re: Is lapping necessary?

Post by brett1868 » 12 Oct 2016, 11:35 pm

The torque wrench is a reasonable quality entry level tool but does the job and works well as a screw driver. Watch the video in the link I posted previously if not already watched. It's a relatively simple process though take your time and check the progress often, it's easy to take little more off but impossible to put a little back. Another tip is once the bases are bolted up I grab a plastic bag, cut a couple nicks in it for the bases to protrude then tape it down. What I'm attempting to explain is that you don't want to get any lapping compound in the action so cover / tape it up very well before starting and ensure you thoroughly clean the compound off everything once done.
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Re: Is lapping necessary?

Post by junjun » 14 Oct 2016, 12:01 am

brett1868 wrote:The torque wrench is a reasonable quality entry level tool but does the job and works well as a screw driver. Watch the video in the link I posted previously if not already watched. It's a relatively simple process though take your time and check the progress often, it's easy to take little more off but impossible to put a little back. Another tip is once the bases are bolted up I grab a plastic bag, cut a couple nicks in it for the bases to protrude then tape it down. What I'm attempting to explain is that you don't want to get any lapping compound in the action so cover / tape it up very well before starting and ensure you thoroughly clean the compound off everything once done.


Will do. Thank you very much for the advice.
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Re: Is lapping necessary?

Post by MalleeFarmer » 14 Oct 2016, 7:43 am

I will say no. But it's beneficial. I have a damaged scope from Talley Lightweight mounts they put 2 deep indents on either side of both rings read that 8 dents on a $600 scope. Now they're not the best quality but they're good. I also have a couple sets of EGW scope rings $200 a pair. They're as close to perfect dimensions as you'll get and I've lapped one set and did take a little material off. The set I didn't lap haven't damaged the scope but since the talleys I won't mount a scope without lapping.
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Re: Is lapping necessary?

Post by Homer » 14 Oct 2016, 3:04 pm

G'Day Fella's,

JunJun, how long is a piece of string?
It all depends on the individual rifle, scope base and rings.
The problems you are facing, is the multiple combination of different factory tolerances.
Even if all of these parts were made in the same factory, there would still be normal manufacturing tolerances, that would cause variables.

Here are a couple of example, of why I lap rings;
DSCN0773.JPG
DSCN0773.JPG (445.92 KiB) Viewed 4483 times

DSCN0774.JPG
DSCN0774.JPG (387.75 KiB) Viewed 4480 times

I hope you can see where the Steel Ring Material has been lapped/removed (Silver colour), and the remainder is still intact.
The Front/Left ring, has benefited most from this lapping job, as it was at a bit of an angle, compared to the Rear/Right ring.



The reason I generally lap rings in place, is to eliminate these tolerance variations.
The way I look at it is, you have probably heard of "Bedding a Rifle Action", well "Lapping the Rings" is basically doing the same thing for your scope!
The biggest problem you will be facing JunJun, is actually finding a person that actually understands what it is, that they are trying to achieve!
So be careful, as this task can be overdone by persons that don't truly understand, what it is they are trying to achieve.

Hope that helps

Doh!
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Re: Is lapping necessary?

Post by Homer » 20 Nov 2016, 7:10 pm

G'Day Fella's,

Here is another example of scope ring lapping, this time on Nightforce 34mm Aluminium triple screw rings.
DSCN1684.JPG
DSCN1684.JPG (480.63 KiB) Viewed 4428 times


Here is a close up of the front ring.
DSCN1685.JPG
DSCN1685.JPG (706.18 KiB) Viewed 4428 times


And a close up of the rear ring.
DSCN1686.JPG
DSCN1686.JPG (700 KiB) Viewed 4428 times


Then there is the finished product.
DSCN1689.JPG
DSCN1689.JPG (537.24 KiB) Viewed 4428 times


Doh!
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Re: Is lapping necessary?

Post by southeast varmiter » 21 Nov 2016, 3:30 pm

Gave up on need for lapping by buying a set of burris signature rings with inserts.Can also adjust your moa cant up to 40Moa
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