Have you slugged your bore? If not, then no matter who makes a hard-cast bullet, if it's not the same or slightly bigger size as your bore, you will get leading. Is it a micro grove barrel? Those are NOT considered the best for cast lead bullets.
Few of the commercial lead bullet makers will supply custom sized bullets. There's a couple that will, but only after you have slugged your barrel and worked with them on which alloy and size you need. One is this guy;
http://blackjackhill.com/
He's solved lead bullet shooting problems for a lot of people. Now he's getting into custom swagged jacketed bullets.