How fast you can push a cast bullet is determined by many variables. Bore condition, alloy hardness, bullet design, bullet lube..etc.
but.. to give you an idea, I shoot a 180gr 358 gas checked bullet cast out of straight air dropped wheelweights from my 357 Maximum Handi-rifle at 19-2000 fps with no leading. I plan on backing it off to about 1800 to see if accuracy improves.
Ian