Precision Delta--for sure!
, P-D makes 9, .40 and .45 slugs. I know...as I've bought many thousands
However, they don't make a jacketed .357" slug of any weight. They don't make a jacketed .429" of any weight. Boy, I'd do backflips if they churned out a 100 grain .312" jacketed slug, but they'd only be selling bullets to the fifteen of us that enjoy playing with the "one foot in the grave" .327 Federal Magnum.
Believe me, I'm very well aware of Precision Delta, but when I mentioned in my post that finding bulk jacketed in sizes OTHER than 9, .40 and .45, it was with P-D very clearly in mind.