The Lyman cast bullet manual data is pretty much the gold standard, and it has a pile of recipes for the .30-30 using pistol and shotgun powders. If your bullets are plain base (do not have gas checks), you should stay in the sub-1500 ft/sec MV range. If you want to get closer to 2000 ft/sec, then you should use gas check cast bullets. Further, the slower powders such as 2400 and IMR 4227 are the ticket for lead bullets at higher velocities. I personally prefer IMR 4227 with my .30 gas check lead bullets in various cartridges, clear up to .30-'06. I don't attempt to go beyond 2000 ft/sec in any .30 caliber rifle.

My personal experience in using plain base cast bullets in the .30-30 has not been good. I could never get them to print tight groups.