100% it's the .458 shoulder chamber.

I tried Lee and they are not taking custom orders, RCBS is a no go, CD4H will do it but it's 4 months out. Any other source?

I think I can run the 400 basic brass into my 450-400 sizer die and do a light load with Hornady 300 gr to form brass. I'd rather use the right dies if possible though.

Anyone have a used set for sale? Another source?