For obtaining proper final slug dimensions and diameter accuracy, is there an accepted size “above nominal bore” of the lead ball one uses to slug a barrel? I don’t want to barely kiss the edges and have little surface to measure, however I don’t want to have to slam the gun with excessive force to swage a giant ball through. I’m going to have to buy a whole pound of balls to get the one or two I need, so I’d like to know what’s accepted as common knowledge before buying. Thanks