Written by cmshoot
First, mount up your scope base and the bottom half of the rings.
There is a bit of disagreement as to whether or not you need to lap the top halves of the rings as well as the bottoms. Personally, I lap the tops and bottoms. My theory is that if there is a flaw in the top halves, it could still cause problems when I tighten the scope up in my freshly lapped bottoms. Plus, if done correctly, it won't hurt anything, so why not do it.
1. Apply the lapping compound to the lap and the bottom halves of the rings.
2. Install the top halves of the rings. I make sure that I have an even gap on both sides between the tops and bottoms of the rings. I want to snug the tops down enough that I can just work the lap.
You'll want to mark the top halves of the rings so that if you ever take them off, you can get them back on exactly as they were. You'll want to keep them not only as front and rear, but also keep them oriented in the same manner (i.e., the front of the front, the front of the back). I do this by filing 1 small nick in the front of the top half of the front ring and 2 small nicks in the front of the top half of the rear ring. Now, if I take them off at a later date I can easily keep them oriented properly when I re-install.
3. Work the lap back and forth, and in a twisting motion. Only work it for about 30 seconds on the first go 'round. Remove the lap and wipe all the lapping compound of the rings (I use denatured alcohol) so that you can check for contact. Don't try to get 100% contact. Every time I've seen someone get 100% contact they end up removing too much metal from the rings, ruining them, and good rings ain't cheap. I usually go for about 75 to 90% contact.
If you haven't achieved the proper contact on the first cycle, start again at Step 1 and repeat until you do.
4. Once you get proper contact, remove the top halves and insure that you get all the lapping compound off your rings, you don't want to grind it into your scope. If they're steel rings, I'll hit the freshly lapped surfaces with some OxphoBlue from Brownell's.
5. Go back to the scope mounting instructions and mount your scope. Viola!