Lapping a Scope? Why?

[Off in the Bushes]

How important is scope lapping?
Why is it done?
Once mounted and scope is sighted in what difference does it make?
Is this how not to get ring marks on you scope?
Are there certain calibers that this should be done on, or is it any firearm?
Can one rent these from fire arm dealers or do you have to buy the kit?
When dealer provide scope mounting are they lapping them, or just mounting rings positioning scope and out the door?
Is this old school when quality control on the tolerances of rings and bases could be out quite a bit?
With CNC machining now is this still and issue?
It doesn't look difficult to do just a little time consuming.

[elkhunter11]

I hope you aren't lapping the scope.

Rings should be lapped when the rings do not line up perfectly. If left out of alignment, there will be forces exerted on the scope tube, that can mark the tube, or if bad enough, can interfere with the operation of the scope adjustments. If the receiver is drilled and tapped perfectly, and the rings are made perfectly, lapping isn't required, but that isn't always the case. If you use a solid rail, that fits the receiver properly, or is bedded, no lapping should be required. As to whether the dealers lap rings or not, that depends on the dealer. As to renting out their lapping bar, not likely, as then they don't have it while it is rented out.

[Pathfinder76]

Yes it can be an issue, it will help with ring marks, and it will aid in less stress on the scope tube.

[Curly Bill]

The only rings personally that I’ve seen that don’t need lapping are NEAR MFG. My biggest concern is contact and pressure points. If you Lapp a pair of rings you see how truly flawed they are by the high spots you lapp off. A good Lapp job gets you a lot more surface area of the ring touching the scope resulting in a better hold, less chance of movement and no dents in the scope tube

[Off in the Bushes]

So would it make the difference of having pie pan groups at 300yds down to coffee mug sized groups? Or does it just hold zero better as there is more surface area of the ring holding the scope?

[AndrewM]

Just use Burris signature or something similar with an insert if you don’t have many rifles and don’t want to purchase a lapping kit.

[AndrewM]

Originally Posted by Off in the Bushes

So would it make the difference of having pie pan groups at 300yds down to coffee mug sized groups? Or does it just hold zero better as there is more surface area of the ring holding the scope?

Depends how far your rings are out of alignment. Some rifles it wouldn’t make much if any difference. Some it would make a world so hard to say without seeing the alignment of your rifle.

[dogslayer403]

Originally Posted by Off in the Bushes

So would it make the difference of having pie pan groups at 300yds down to coffee mug sized groups? Or does it just hold zero better as there is more surface area of the ring holding the scope?

More likely to affect tracking than group size

[Kurt505]

Originally Posted by Off in the Bushes

So would it make the difference of having pie pan groups at 300yds down to coffee mug sized groups? Or does it just hold zero better as there is more surface area of the ring holding the scope?

It’s all up to the end user and if they’re satisfied with their end results. Without mounting the scope and firing it it’s impossible to tell if lapping the rings was worth it. What lapping will do is eliminate the rings as a problem with accuracy should one come up when you’re shooting. Preventative measure, once you’ve installed your scope and take it to the range and find you can’t get proper windage, elevation, or you find your bullets hitting like a scatter gun and you never lapped your rings, then you have to take it appart and try again. It takes 10 minutes to lap your rings the first time you mount them on your rifle. Seems worth it to me but may not be worth it, or even needed.

[Off in the Bushes]

So if I am understanding correctly it really isn't needed but it helps eliminate issues that you may or may not have. So basically it is insurance that the scope is properly aligned and doing its job, eliminating one factor of the equation.

[obsessed1]

Use centerpoint alignment bars. It will tell you right off how good your rings are. Sometimes even good rings can give 25% or less contact surface. I choose to either use Burris z rings with inserts or lap. Why not eliminate any variables that could effect proper tracking.

[Pathfinder76]

Centerpoint alignment bars are no good. They will not tell you if you have vertical misalignment. Flat bars are better for this.

[obsessed1]

Originally Posted by chuck

Centerpoint alignment bars are no good. They will not tell you if you have vertical misalignment. Flat bars are better for this.

Might be talking about different things my bars have center points that show any horizontal and vertical alignment.

[elkdump]

Originally Posted by Off in the Bushes

How important is scope lapping?
Why is it done?
Once mounted and scope is sighted in what difference does it make?
Is this how not to get ring marks on you scope?
Are there certain calibers that this should be done on, or is it any firearm?
Can one rent these from fire arm dealers or do you have to buy the kit?
When dealer provide scope mounting are they lapping them, or just mounting rings positioning scope and out the door?
Is this old school when quality control on the tolerances of rings and bases could be out quite a bit?
With CNC machining now is this still and issue?
It doesn't look difficult to do just a little time consuming.

I always lap the scope rings when mounting/changing a scope

I always use powdered mounting rosin, wether just lapped rings or already lapped but moving scope, all calibers .17 HMR to .460 Weatherby and beyond,

I always torque base screws and ring screws

Never have scope moving issues ,

[Pathfinder76]

Originally Posted by obsessed1

Might be talking about different things my bars have center points that show any horizontal and vertical alignment.

We are talking the same things. Lay those bars on the table and your points will touch even at a 90 degree angle.

[elkhunter11]

Originally Posted by chuck

We are talking the same things. Lay those bars on the table and your points will touch even at a 90 degree angle.

You can have both vertical and horizontal misalignment, and the points can still meet.

[obsessed1]

Originally Posted by chuck

We are talking the same things. Lay those bars on the table and your points will touch even at a 90 degree angle.

That would only be true at a certain point between the rings would it not? Slide that point toward the front or rear ring and the points will show miss alignment would they not?

[Pathfinder76]

But where is the correct point? I turn mine around.

[Salavee]

Originally Posted by elkhunter11

You can have both vertical and horizontal misalignment, and the points can still meet.

What alignment tool are you using? I"m using Sinclairs and have'nt found that so far.

[elkhunter11]

Originally Posted by Salavee

What alignment tool are you using? I"m using Sinclairs and have'nt found that so far.

I use a 1" bar and do a minor lapping, and look at the pattern. If the initial pattern is good, I don't lap any more, if the pattern is poor, I lap until it is good. I have tried the two pointed bars, but I prefer my method.

[Salavee]

Originally Posted by Salavee

What alignment tool are you using? I"m using Sinclairs and have'nt found that so far.

They are used to align the 'scope with the rings? If the rings aren't set to align with the bore that's another matter isn't it? If the bases won't align either vertically or horizontally with the bore that's another matter? Just asking.

[260 Rem]

It makes sense to lap rings if it is needed ... I have never lapped and never had an issue with ring marks, holding zero, or adjustment. I attribute my good fortune to primarily using one piece bases and decent quality rings (Leupold).

[Salavee]

Originally Posted by 260 Rem

It makes sense to lap rings if it is needed ... I have never lapped and never had an issue with ring marks, holding zero, or adjustment. I attribute my good fortune to primarily using one piece bases and decent quality rings (Leupold).

I've never found it necessary to lap decent quality rings either but I am a firm believer in getting them set squarely mounted in the rings. That, coupled with a good grid type boresighter seems to get the job done every time.

[AndrewM]

I don’t have a one piece base but curious for those that do. Do you ever need to lap a quality one piece?

[AndrewM]

Originally Posted by Salavee

I've never found it necessary to lap decent quality rings either but I am a firm believer in getting them set squarely mounted in the rings. That, coupled with a good grid type boresighter seems to get the job done every time.

I have a poor drilled 303. It needed alignment and lapping even with the best rings. I imagine good quality rifles shouldn’t have that issue.

[Pathfinder76]

Originally Posted by elkhunter11

I use a 1" bar and do a minor lapping, and look at the pattern. If the initial pattern is good, I don't lap any more, if the pattern is poor, I lap until it is good. I have tried the two pointed bars, but I prefer my method.

This is also how I do it. Here is an alignment tool.

http://echolsrifles.blogspot.com/201...tools.html?m=1

[Salavee]

Originally Posted by AndrewM

I have a poor drilled 303. It needed alignment and lapping even with the best rings. I imagine good quality rifles shouldn’t have that issue.

If the base screws align perfectly with the bore there shouldn't be any issues
It's a rare occurance with most good quality rifles but I have seen a couple of instances where the mounting holes on the receiver were misaligned'

[Salavee]

Originally Posted by obsessed1

Might be talking about different things my bars have center points that show any horizontal and vertical alignment.

Those sound like Sinclairs, the same as I use. They show both horizontal and verticle alignment. Impossible for them to do otherwise.

[Salavee]

Originally Posted by elkhunter11

You can have both vertical and horizontal misalignment, and the points can still meet.

Unless we are talking about different tools, the Sinclairs, when mounted level in the ring's, the points cannot precisely meet .. only when perfectly vertically and horizontally aligned.

[Salavee]

Originally Posted by Salavee

Unless we are talking about different tools, the Sinclairs, when mounted level in the ring's, the points cannot precisely meet .. only when perfectly vertically and horizontally aligned.

https://www.sinclairintl.com/userdoc..._Tool_Inst.pdf