One other thing I thought of last night. Giving the gunsmith that built it the benefit of the doubt, it probably left his shop working correctly, that makes me think something mechanical has happened to keep the case from seating properly in the chamber. Another place to look will be under the extractor. There should be a small screw on the underside and between the barrels, remove that screw this will allow the extractor to be removed. If powder residue has built up in that area it prevent the extractor from seating all the way down, thus holding the case up slightly, again .007 isn't very much, it would not take much build up to cause this to happen.
Bob