Getting back to the initial question asked here by armbar, yes, sxs answered it well, and I have also found that what bonanza had to say about using a standard feeler gauge of .001" thickness to check on/off face condition is very practical, much better than using a piece of paper to do the same thing, because some folks simply cannot assess the situation well by "eye" without using such a feeler gauge, which is practically a foolproof method. Remember too, that when gun is on face, you will normally have a small gap of around .003", maybe .004" or so between watertable and barrel flats, at base of standing breech--barrel flats should NEVER be touching the watertable at that point.