i was reading an old thread in this section about scope mounting and they were talking a lot about "lapping" the rings when mounting scopes. can anybody tell me what it means to "lap" the rings? and all these different ideas on how to make scopes left and all that jazz confuses me. i understand the concept of vertically aligning the reticle, but leveling the scope make my head spin. are we leveling the scop in relation to the bore of the barrel, or are we leveling the scope in relation to, say water?