Scope Ring Lapping

[Wildyams]

I have a Winchester m70 stealth in 308. I'm planning on turning it into a long range target gun.

I just ordered a new scope and was wondering if lapping the rings has any affect on accuracy or anything?

http://www.midwayusa.com/product/87...ing-scope-ring-alignment-and-lapping-kit-30mm

^Thats the kit I'm looking at getting. Is it worth the $40 or should I just get a pound of powder and a box of bullets instead?

 

[mljdeckard]

It certainly can make a difference with a more solid fit. Particularly with other than top-shelf scopes and rings. For example, there is going to be better fit with Badger Ordnance rings and a Nightforce tube than with rings and a Simmons scope from Walmart. If you've already invested in a rifle worth some tuning, don't go cheap.

 

[Wildyams]

the scope I'm going with is a Vortex Viper PST 6-24x50. The rings I'm using are Burris Xtreme Tactical rings (that is, if the set I have is an okay height)

 

[madcratebuilder]

Most quality ring sets do not need to be lapped. It's a good idea to check if you have the equipment. I have a couple of sets of the Burris Xtreme rings and no lapping was required.

 

[Sav .250]

Maybe I`m just lucky but have never had to do that. Never even thought about it.

 

[alsaqr]

One should check ring alignment before installing any scope in any rings. i've seen several scopes ruined as a result of installing them in out of alignment rings. Some rings require so much lapping i will not install them.

 

[LTR shooter]

I see a lot of used scopes on sale in the gun boards or places like eBay where ring marks are visible. This is something lapping prevents.

 

[SwampWolf]

Maybe I`m just lucky but have never had to do that. Never even thought about it.

Me either-and I've mounted a lot of scopes over the past forty years or so. I'm not saying that lapping the rings is not a good idea; only that I've never found it necessary nor even especially beneficial. I don't think there's any downside to doing it and concede that there are doubtless specific circumstances where it constitutes a solution to some dimensionally mismatched scope to rings relationships, only that I think the procedure (lapping the rings) is a little over-rated in terms of its need and perceived effectiveness for most scope mounting situations.

 

[Cesiumsponge]

I've never lapped rings I've used (Burris Xtreme, Burris Signature, Leupold Mk4, Seekins Precision) and I can't see how they can ruin the scopes I have used (SWFA SS, Leupolds, US Optics) unless the scope is built like a featherweight.

 

[Bogow]

I went back and forth with the "to lap or not to lap" dilemma. I finally broke down and bought the wheelers kit. I used the kit on the last three scopes that I mounted and Based on what I learned I will not mount another scope without lapping.

Plus it's fun, easy, and when you are done you know the scope is mounted perfectly.

 

[j2crows]

If you do decide to lap...Don't over do it!! I've personally seen scopes on .30 rifles slip because the rings wouldn't tighten enough after over-zealous lapping. I use a ring alignment tool to align my rings and then determine if the rings need lapping. Remember it doesn't take much lapping.

 

[gamestalker]

I've only had to lap on ring set. They were Z rings and had been some how gotten lightly dinged up. Other than obvious damage or imperfections that will interfere with the necessary solid fit, I see no reason to lap rings.

 

[HOOfan_1]

I've only had to lap on ring set. They were Z rings and had been some how gotten lightly dinged up. Other than obvious damage or imperfections that will interfere with the necessary solid fit, I see no reason to lap rings.

I bought a pair of Z rings which apparently were drilled wrong. When you lined up the screw holes for the top and bottom halves of the rings, they were our of round. Maybe something like that is what lapping would fix...I just returned them to the store instead.

 

[Jdillon]

Personally, I lap all of my rings before mounting a scope. Why take the risk of damaging an expensive scope if the rings are not properly aligned. Inexpensive and easy to do.

 

[Cesiumsponge]

Who is damaging their scopes? Anyone have first-hand experiences or are all these "I heard from a friend of a friend" situations? I'm skeptical about everything and this is no exception. Is this happening on high quality rings and scopes, or flimsy mounts and scopes? What's the point of coating rings when you're sanding away the coating?

I've measured my rings for perpendicularity and axial alignment in the past. The last pair I installed were Seekins rings which come in serialized and matched pairs through the manufacturing process and it falls within .0005" on all critical dimensions. On precision rifle forums, folks aren't lapping their rings and these are hard-use rifles that get kicked around in the dirt and withstand magnum or BMG calibers. When people are claiming damage, are they talking about cosmetic ring marks on the scope tube? Every set of quality rings I've ever come across spec about 65-75 inlb on the base and 15-25inlb on the rings. I've never seen a quality scope damaged by something as innocuous as rings. I've DROPPED my rifle on my scope objective before with absolutely no damage to the scope.

I've never encountered this issue, and it is a completely ludicrous idea that I have to buy an unfinished product that requires finishing operations on my end to get functional or it'll somehow destroy a quality optic.

 

[Old Dog Man]

Lapping rings

I don't understand why some don't or won't do a simple check to make sure their scope is not mounted in trued up rings. The rifle reciever is made with + or- dimensions so are the base and rings. Once these factors are added together what is there that would make one expect everything to be perfectly true and centered? Being a smith I have seen every combination you could imagine. I would recommend to at least check your combo and then decide what you would prefer to do. It's also a good idea with the twist in front ring to lube the ring and work it back and forth so it does'nt torque the scope tube when adjusting the rear windage screws. I've seen them so tight I could hardly turn them into the base. Do yourself and your equipment a favor and do the job right. Al

 

[Norrick]

lapping your rings will give them a better grip on your scope, so there is less of a chance that it moves during repeated firings, which will keep your zero. It doesn't really make it any more accurate, but it doesn't hurt any. A nice consequence of carefully lapped rings is that it won't ruin your scopes finish. If you use high quality rings on a one piece base then you probably dont need to, since the base itself will line it up nicely if the rings are made equally well. If you use a two piece base then it would probably be better. Some steels are a lot harder to lap I've noticed than others. I had a pair of burris rings that melted away like wood, and some ruger rings that actually seem to be making the lapping bar smaller.

 

[alsaqr]

i have seen two very expensive scopes ruined by out of alignment rings.

 

[Jdillon]

To reply to an earlier post, I have seen scopes damaged by improper ring alignment especially those mounted with dovetail bases. Certainly there are instances where high quality rings and bases machined to very tight tolerances may not require lapping but for most shooters that would be the exception and not the rule. I recently mounted a Leupold Var III 6.5x20 LR on my No.1 V and the Ruger rings were poorly aligned. Realigned and lapped the rings to assure a proper fit. If not, the scope tube would have been torqued with the resulting damage. Like I said earlier, its inexpensive and easy.

 

[Old Dog Man]

Lapping rings

One of my custtomers brought in a bench rest rifle to have a Nightforce scope and rings mounted, I asked him about lapping the rings, he said the instruction sheet said not to. After mounting the rings I turned the lap bar just a little bit and showed him the results, and asked him if he wanted me to mount the $4000 scope in the rings. He said no lap them. Right decision. Al

 

[arizona98tj]

Most quality ring sets do not need to be lapped. It's a good idea to check if you have the equipment. I have a couple of sets of the Burris Xtreme rings and no lapping was required.

Did you actually check them before you determined no lapping was required? Just asking.

Here is a pic of a Burris Xtreme ring....part way through lapping process. As you can see, it required lapping. This was the 2nd set pair of Burris Xtreme rings I've mounted. The 1st set required lapping too. Maybe I was just really unlucky getting two sets in a row that were a poor fit and purchased a year apart.



FWIW....I'll never consider a scope properly mounted without first checking the alignment and lapping as appropriate.

 

[ball3006]

Never lapped a set of rings. Never damaged a scope. But, I know what I am doing when I install a scope.......chris3

 

[Longrifle2506]

Lapping is a good Idea. It eliminates uneven surfaces on the inside of the scope rings, so the rings will not put any undue stress on the scope tube. I wish I had lapped my Leupold PRW rings, because they marked up my scope. They fit real tight on the body. What's worse about it; is that I have lapping grit and bars(Wheeler); I believe I'll lap my next rings.

 

[MCMXI]

The vast majority of rings that I've installed have needed lapping as indicated by the misalignment of alignment bars. Some one-piece scope mounts have too. I've mounted 1", 30mm and 34mm rings from Leupold (Mark 4 steel and aluminum), Seekins, Warne and Talley ... probably 15 sets or more. I've also mounted numerous one-piece scope mounts from GG&G, LaRue and AI. The LaRue and GG&G mounts haven't needed lapping but all three 34mm aluminum mounts from AI needed lapping.

 

[Cesiumsponge]

Based on the photo of the coating being lapped off, that ring is no more than .001"-.002" out of round, referenced to the lapping bar, with a slight low point. That dimension corresponds to one fourth or one half the thickness of a sheet of printer paper. It looks more like a cant issue because axial alignment is correct but the coating removed is pitched. Perhaps the issue is compounded due to the "rail" it's mounted on. It doesn't appear to be a true picatinny as the manufacturer took liberties with the mil-spec, and it's a picatinny mounted on a receiver, stacking tolerances.

I don't know if anyone here has taken measuring instruments and measured how far off the rings might be before lapping away because anodizing coatings are very thin, and steel coatings like black oxide are vanishingly thin, 0.00005" thick. A thickness of 0.00005" corresponds to a sheet of paper being split thickness-wise 80 times.

If people are making such a big fuss about lapping rings, has anyone ever tried to centerless grind their scope tubes into roundness? Has anyone taken a precision micrometer and measured the OD of their scope tube? Has anyone ever measured the ID of their scope rings? By lapping material from the rings, you're fitting the rings to the lapping bar. You aren't fitting the rings to the scope tube. To precision-fit two mating surfaces together, you do it with Prussian Blue and make repeated markings, knock off the transferred high points, and repeat until you get as many bearing points as you require.

Has anyone taken the time to measure the TIR of their scope tubes at the two points where rings will be mounted? Your scope body roundness is probably ovoid by .0005". The tube probably tapers in diameter from one end to the other, and TIR will register a measurable figure given that long, skinny tubes of aluminum are not perfectly round and will have an off-axis bend to them

Maybe it's time I market a scope tube grinding kit. I have no doubt that not all rings line up perfectly, but attacking the rings is only half the equation, if folks are that bent on getting a perfect fit. As mentioned by another poster above, you can remove too much material and ensure an incorrect fit once you introduce the stresses of the cap screws clamping down on the scope tube.