Well, all the bullets come out so near .457" that they are hardly touched by the sizing die , just too heavy for their declared manufactured weight. I don't shoot cowboy loads, just medium range - 500 - 600m with my High Wall.
Uberti themselves recommend a soft-lead as near as dammit 100% lead mix, though, something I can more or less manage from [legally-acquired] pre-WW1 church lead roofing and flashing.
tac