No offense, Hand Skills, but your answer above makes me question whether you've really thought this through. And certainly makes me question whether you've actually ever lapped any rings. You can feel the clamping force increase as you do the lapping process. When you first start, you can tighten the rings down pretty good and it's still easy to turn the lapping tool. As the bore of the rings become concentric AND perfectly round, as you begin to tighten down each ring, suddenly is becomes very hard to turn the lap even with the screws minimally tightened.
Do you always lap your scope rings?
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ntsqd
Well-Known Member
Having honed and lapped many parts and many fits outside of firearms over the last ~40 years I have some experience reading the marks left by the process. Those marks told me that the rings were not round, but that the alignment to the action was reasonably close. Not perfect, but close. That is how I know, past experience with similar situations.
I have also lapped a one piece scope base to fit a Savage action. I did this by making a lapping bar in my lathe, and then lapping the base to it. Lap, check fit, lap, check fit. It was a simple but laborious process, but the fit of the ring lapping bar told me that the rings weren't the problem then.
I think it's laughable how many advise against it when they don't know anything beyond what the mfg tells them. Which may or may not be correct and is more likely how their marketing wants the optics of their parts to appear and their returns dept. being tired of dealing with rings that were lapped by someone with no clue. If you don't wish to do it then don't, but don't belittle those who do and can do it properly. Lapping isn't rocket surgery and it is a method to achieve a better fit, but it also isn't something that everyone should be doing.
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We use something similar but with a machined 1" and 30mm aluminum bar instead of the scope. Then we check the alignment to the bases and modify or change the base, if needed
Good idea. I have lapping bars. Next time I will use one of those instead of the scope.
Do it a lot like the Feenix vid above. Can then file the rail a bit where needed for a good fit.
itchytriggerfinger
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Did the manufacturing process get THAT much more precise in the last 20 years?? The first Nightforce scope I bought around 1999 stated the scope warranty was VOID if the scope was mounted in rings that were NOT lapped. These were Nightforce rings.
This is the reason I starting lapping scope rings.
This is the reason I starting lapping scope rings.
It has gotten a lot better for sure and depending on what I'm dealing with, I will still at least lap slightly just to check. To think you can just trust all the different manufacturers in a rifle/scope system is silly.
Hand Skills
Well-Known Member
This is pretty much how I bed Talley rings on 'open' style receivers. After aligning the rings as close as mechanically possible, I torque the front down, and remove the rear.
Install set screws in the rear reciever holes (proud, to index the holes and prevent epoxy from leaking in).
Then set the rear base on the the receiver and tighten down ring clamps. I'll look at how much the rear ring base floats to estimate how much epoxy is needed, then remove front ring cap.
Remove scope (with rear ring attached). Apply release agent to receiver, epoxy to ring base.
Re-install scope (torque front ring cap). Let epoxy set.
Remove scope and rear set screws, install rear base, confirm alignment, install scope.
No ring marks. Less work than lapping.
Good for you. This topic comes up on the forum regularly. I'm beginning to think my time will be better served creating a tutorial rather than responding to ad hominem.
Lapping has its place. It also has its limits. You talk about marks, and I hear you. What if there was a way to align parts, necessitating no lapping and leaving no marks? Taking your parts experience for example, when it comes to concentricity, ask yourself this; would you lap a bearing housing? Or would you index and sleeve it?
I'm sorry to have come across as belittling, in retrospect 'fools errand' may have been a bit strong.
I have used Nightforce rings on all of my Nightforce scopes and never lapped any of them until I took on the two mile range. I incurred many problems until I was asked if I had lapped my rings. Curiosity got to me so I tooled a piece of round stock brass to 34mm 24cm long and painted it with a permanent black marker. I inserted it lying on the bottom of my rings and snuggled the tops down just to where I could drag the piece slowly out of my rings. Although they were making good contact of over 70%, by no means were they close to 100%contact. I took my findings to my Smith and he concluded. I let him lapp them in my presence as I didn't have a 34mm lapping tool. This solved my problem and I was able to make the shot the following weekend.
What was the problem you were having? Was the POI changing/walking as you dialed elevation needed for a 2 mile hit?
I never attacked you. Just asking questions. I do see where you went from saying lapping has no place to where it does have a place all within a handful of posts. So we are making progress.
What was compensated for (we later found out) was a small burr in the rings rail mount. It would creep a half MOA one direction and then fall all the way back. You just never think that something so trivial can cause you a miss until you shoot exceedingly long range. Re-educated me by far!
ntsqd
Well-Known Member
Re: Bearing housing; does it have to be concentric & coaxial with other bearing housings, or does it just need to be round? And how round is round enough?
If it needs to align with others, and it/they are not, and/or it is not round enough (to size) then I'm going to hone or lap it inline with all of the others at the same time. If it/they are aligned well enough and are round enough for the purpose then move on to the next item that needs to be addressed. Why do work that gains you nothing?
It is certainly possible to lap rings too much and end up with rings that are over-size that will never grip a scope tube securely enough. When that is a possibility with no easy method to recover from it then the grit choice should err on being too fine. A too coarse grit just means that you can go over-size much faster than you thought.
In the case of the rings that I had to lap there were no separate bases to first true. In the case of the base that I lapped, it was pretty clear, before even getting as far as installing & checking ring alignment, that the base needed some work to fit to the action correctly.
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