http://www.saami.org/PubResources/CC...Winchester.pdf .475" at the base? If you mean the web area, that too big. Normal dies does not size down that far. Plus your die seems on the tight side. Just a quick guess.
The shell holder has a deck height, the deck height of a shell holder is .125”, then there is the radius at the opening of the die to be added.
'’.475" at the base?'’ Measure before and again after, forget that, the cases were purchases as having been fired, if in fact the case head is .475 in diameter and the cases have been fired once the additional .005”+ indicate the case head was hammered the first time it was fired, if the case has been fired multiple times the additional .005” upset/crush of the case head indicates case head is excessive, then there is the ‘everything being relative’ if the case head has expanded the primer pocket has been expanded and the flash hole has been expanded.
F. Guffey