To Lap or Not To Lap?
Before we move into that question I’ll quickly explain what ring lapping is for those who may not be familiar with the process.
What is Lapping?
In short lapping is essentially the process of sanding away material on the rings to provide a more custom fit to the scope. Precisely mating the two surfaces together. In general, your scope rings will make only some surface contact with the scope itself and in areas of low spots there will be no contact. Although not catastrophic this is not ideal and provides an area of potential accuracy degredation and uneven stress on the scope tube.
Lapping the rings trues them to the scope and increases the surface contact between the two giving you the optimal fit.
Is Lapping Necessary?
This topic is often debated by both sides of the issue. From my perspective it can only serve as a potential benefit. There is no downside to doing so other than the small amount of work involved.
Because each weapon and base may have slight variance (as well as the scopes) lapping allows a custom fit for the individual setup you have. While modern machining has surely come a long way and can produce some very true products, it cannot account for every weapon and base as well as minuscule deviations. These may have simply occurred with wear over time or even from the factory. Lapping then essentially sands the rings down to provide a complete custom fit with that specific setup. While transferring to another weapon may allow a close fit I would imagine in most cases; the process should be completed again for the same reasons already mentioned. I thought a little on this and believed there could be two ways to do this effectively. Easiest would likely be to buy a new set of rings for the new weapon. The second method I suspect may work would be to color the rings with a permanent marker before lapping. This would allow you to once again see the high and low spots. The challenge here would be the potential to over lap the second go round.
What You Need
- Lapping Bar
- Lapping Bar Handle
- Lapping Compound
- Alignment Pins
- Scope Rings
- Scope Base
- Mount for the firearm
- Acetone or other degreaser
The Process in Pictures
Mount the rifle and check for level on the platform, weapon, and base.
PreCheck the scope position desired. Paying attention to eye relief, general fit and placement.
Place the alignment pins in the ring bases facing each other (top ring loose). If the pins are perfectly aligned no lapping is necessary.
Prepare Rings for Lapping
Remove the alignment pins. Split the rings. Clean the rings and apply lapping compound on top and bottoms ring interior surface.
Lap the Rings
Install the lapping bar and begin to rotate and move back and forth slowly. Occasionally tightening the ring screws as needed to keep firm pressure on the bar. After several passes, remove the bar, degrease the rings and check your progress. Ensure you maintain the same top and bottom rings together during this process as well as maintain the same orientation.
You will be able to gauge your progress by looking at the inside of the rings. Once you have removed about 90% of the anodized coating you are complete with the lapping.
Wrapping it up
Once complete I like to do another check with the alignment pins. Though it really shouldn’t be necessary I just prefer to do it.
At this point you are complete with the ring lapping. Leave the bottom rings installed on the base. You are now ready to begin the scope mounting which is a task for another article.
If you enjoyed this article please share your thoughts with us in the comments below. Do you have something to add, or do the process differently let us know!
See you again soon.