I don't have one to measure so I am going to ask the question here. Is there enough meat in the walls of a Lyman .427 or.440 round ball mold to recut it to a 350-450gr .458 bullet for a 45/70?
I can't tell from pictures if there would be enough material between the mold cavity and the handle slots. Or to put it another way, what is the dimension across the slots on a RB mold?
Greg

Don't have one handy, but I believe it is the standard lyman block, which certainly has enough "meat"

That said it's a bunch easier to just find an apropriate existing mold or have a custom one made.

All bullet moulds for reloading metallic cartridges are from the same size block with RCBS I imagine it would be the same for Lyman. I've done this with RCBS and it is easier to find a mould that is of a bullet much smaller diameter than the size you intend to re-cut to. It works better!