Bill made a .038" thick curved segment which I affix to the table with a C clamp and use to zero the gauge. Works great.

Damascus: I'll let someone within the profession explain personal injury law in the U.S. However, as has been expressed on previous threads regarding a U.S. proof house, most of us have a profound lack of confidence that our moral and intellectual superiors in Washington would not confuse 'safe' with 'it's black and plastic so it's evil' and then decline to prove, and effectively ban, those guns that are not 'good'.