Has anyone tried lapping the crown of your SAR's?  If so, what was the procedure you used?

I've always wanted to know, myself. And why lap vs. just cutting a new crown?

There's a few reasons not to cut.
Cutting imparts heat to the part.  There are ways to control this, such as cutting slowly and cooling the part.  These both increase costs somewhat.  You can also cut a bbl so short you're in violation of the law.

The core problem of course is burrs and imperfect / oblong / damaged / burst crown.  If you can repair the issue with simply polishing it with a mating surface, why cut?