I use a lee production pot with bottom pour. And inexpensive Lee aluminum molds. Use lots of flux. Keep the mold hot. Your first few balls/ bullets may not come out good. As the mold gets hot it will cast plenty of good balls. Buy a can of mold release spray. I try to buy 6 gang molds. Mold 6 at once.
This isn’t 1776. Get some good equipment. You don’t have to spend a lot
Back in the 1970’s competitive muzzleloader shooting was very active. As a yute I cast many many thousands of balls and minies. Sold gobs of them. Sat over an old double burner propane stove for myriad hours with a cast iron pot and Lyman molds. I got used lead plumbing pipe from the scrap yard, something you would never do today. Wheelweights have too much tin in them and don’t work well in muzzleloaders. They are ok for high power centerfire stuff.
Of course today you would not melt down used pipe in the basement because we are aware of the health problems it might cause but it sure was done a lot back then.
Aw, that's cheating.
:-)