looking to shoot a couple of egyptian sniders with .590 smooth bores i bought some fiocchi shot loads for the cases (primed hulls are not in stock anywhere), and measuring the cases and cups noted that the case OD is .633, the case wall is .025, the shotcup is 0.025, and therefore the interior of shotcup is about .536. Lee makes minnie ball moulds at .533 and .540, and lyman makes one in .542. it occurs to me that this gives me forward weighted in an economical package, as shotcups and shotshells are cheap, when they are in stock. with a 410 grain minnie 14-18 grains unique should be quite mild. i have not considered the question of how much black I could get under an unmodified shotcup or how the cup could be modified to make more room for black or trip 7.
has anyone done this or is there an opinion?
thanks