How To Properly Lap Scope Rings

Lapping is advised when utilizing certain scope mount designs to gain optimum performance. Lapping can help with the accurate alignment of the scope rings as well as enhance the amount of surface contact between both the ring and scope tube. Lapping is not advised according to the installation guidelines for Warne Maxima vertically split rings. Why Warne does not advise lapping when so many other ring manufacturers do is a crucial question.

First off, what exactly is lapping? In its most basic form, lapping involves placing some sort of abrasive material between two or more surfaces to create friction between them. This procedure helps contour the surfaces so they fit together better by sanding, polishing, and smoothing the surfaces. In the case of scope rings, the user would combine the base and rings using a steel lapping bar and a lapping compound (essentially an abrasive liquid or paste).

The rings are tightened until the bar can move freely but with some resistance, and the bar is manipulated back and forth. When the lapping job is finished, the bar and compound remove high spots and rough patches while polishing the ring surface that meets the scope tube. 

It can also help ensure that the ring cap is properly aligned with the ring body because it is a regular practice with horizontally split rings. Lapping is a genuine procedure that can increase the performance of some types of mounts, particularly ones with windage adjustment.

The rings are tightened until the bar can move freely but with some resistance, and the bar is manipulated back and forth. When the lapping job is finished, the bar and compound remove high spots and rough patches while polishing the ring surface that meets the scope tube. 

It can also help ensure that the ring cap is properly aligned with the ring body because it is a regular practice with horizontally split rings. Lapping is a genuine procedure that can increase the performance of some types of mounts, particularly ones with windage adjustment.

Because of their basic design, vertically split rings such as Warne Maxima should not be lapped. A horizontal split creates a ring body and a ring cap. The ring body is screwed to the base, and the cap is screwed to the base, creating a vise-like clamping pressure on a scope tube. 

Maxima rings connect to the base, and the bottom of the ring closes. When the top screws are tightened, the ring flexes around the scope tube, exerting hose clamp-like pressure on it. Maxima rings have a single little gap at the top where the ring does not come into contact with the scope tube. 

In comparison to horizontally split rings, vertical split rings begin with more scope tube contact. In comparison to horizontally split rings, vertical split rings begin with more scope tube contact out of the package. 

Lapping is difficult to impossible to execute correctly because vertically split rings must slightly stretch around the tube to tighten. Because the ring is designed to be slightly flexed at the correct torque around the scope tube, it would need to be in that tightly flexed position to correctly lap the ring. 

As a result, the lapping bar cannot move, hence the ring must be slack to lap a vertically split ring. This can be a concern because the ring’s internal surface will change form as the material is removed. The ring is not the correct shape when tightened and flexed around the tube. This might result in high and low locations.

For good reason, windage adjustable, horizontally divided rings are most typically lapped. Windage adjustable rings purposely push the ring away from the base, causing misalignment of the two rings and either a bind on the scope tube or a reduction in holding strength owing to a loss of surface contact. These mounts are then lapping to bring everything back into line and assure optimal operation. 

Because the two ring parts are evenly tightened, a Warne Maxima ring naturally positions itself on the scope base. Because the ring naturally aligns itself, the rings will be in perfect alignment every time as long as the receiver is drilled straight and high-quality bases are utilized.

Why is it significant?

This is what happens when lapping is required. Assume you purchase a nice-looking set of rings but observe a series of fine raised lines above the surfaces of the inner band of material. These finely cut bands might be uneven, causing stress on even a small portion of the scope tube.

When you attach the scope and tighten the top halves of your rings to the lower halves, pressure is formed against the scope tube, and if the rings are not manufactured evenly with a smooth surface, significantly more pressure is induced in one area than another.

What Will You Need to Purchase?

What equipment is necessary while lapping most scope rings? Assuming you are not a gunsmith, you are generally unequipped to handle lapping created using common household tools and will need to purchase at least a basic lapping kit.

I would think carefully about completing this project yourself unless you plan on doing a lot of scope transfer or general mounting work. Assume you’re installing a deer rifle sight and don’t plan on doing it again anytime soon.

How Does the Alignment Look?

If you plan on installing scopes regularly, even for a small store or pals, the instruments of the trade are simple to obtain from a gunsmith product supplier and include the following.

To begin, a scope base ring centering mechanism is recommended. This unit consists of a set of machined alignment instruments that come to a point when they are positioned against each other on a jig mount. The cylinders, also known as lapping rods, are screwed slightly forward towards each other, and the very top of each cylinder must align straight with the other.

Any deviation from this alignment means the scope bases have been installed off-center. In most situations, this is due to incorrectly aligned base drill holes in the receiver rings and rear receiver assembly. While I’ve never seen this in a custom-built rifle, I have seen it in a few factory installations.

How is polishing carried out?

You are prepared to move forward if you have performed this ring alignment check and everything is in place. The top and bottom rings are then polished with a specialized compound to remove any marginally raised areas, leaving you with a pair of rings that is flawlessly smooth.

You will want a lapping tool, which resembles a rifle bolt but is sized at one inch or larger (depending on the size of the scope tube) and ought to be included in any set. Continue with the following after locking the bottom rings into the scope bases system, which is likewise placed on the rifle receiver:

Stack both bottom ring assemblies on top of the lapping tool. The top half of your rings should be positioned in place with the tool, screwed down, but not tightened, to provide space for the cylinder-shaped tool to travel back and forth over both the front and rear scope rings.

Move the device back and forth across both rings gently while using the lapping bar handle and a layer of a silicon carbide-based abrasive material that is available at the gunsmith supply store and applied directly to the ring set.

If there is excess material on the inside surface of the rings, this back-and-forth motion will cause the lapping compound to wear away the high areas of the ring set and remove very minute amours of metal, causing the surface to become consistently smooth.

Apply more polishing compound and tighten the settings on the lapping cylinder once more after the initial adjustment and lapping of the rings. The goal is to remove yet another layer of the ring surface with moderate friction, so only leaves enough room for the tool to continue going around the rings.

What Do Lapping Scope Rings Accomplish?

Lapping, also known as truing up the inside of your scope rings, prevents damage to the outside of the scope tube, eliminates stress on the tube that might compromise the functionality of the internal moving parts of the scope, and improves accuracy by removing any stresses that the scope tube might be placed on your rifle’s action.

Conclusion

I hope this post has given you a better understanding of how to lap scope rings, what equipment is included in lapping kits, what additional equipment will be needed, and when lapping is advantageous.

Is it worthwhile, while using a cheap Chinese scope, to spend hours making exact adjustments and buy a steel lapping bar and polishing compound? Most likely not.

However, it may be a worthwhile exercise if you’re going for the highest level of precision for your bench rest setup and want to make sure that your scope rings are flawlessly aligned, smooth, and in good condition for competition.