I cast my own maxi-balls and they shoot just fine. Some soft lead and your good to go. If your needing lead I have a bunch and can send some your way for a buck a pound and $8.00 shipping, per one rate postal box full. I've got a bullet lube formula given to me here as well, I'd send some of it all made up your way too. Mostly bee's wax, Ivory soap and lanolin (bag balm).
I'd not bother with round balls except for fun shooting, but the lee's should be ok, they engrave when rammed in.