[Unclenick]

The sizing dies all have a radius at the mouth. Add the portion of that radius that is wider than case spec to the shell holder thickness above the rim, and that portion of the length is never affected by a resizing die. For busting bulges, the sizing ring needs simply to be no narrower than the maximum base diameter. That way is doesn't squeeze the head unacceptably. Rather, it just makes sure the portion of the head that a sizing die doesn't touch is still forced within spec to ensure feeding. After that, the resizing die still needs to be used before reloading.