Roofing lead or flashing is good stuff to use. The first melt will be dirty and smelly so best to do it and pour the good stuff into ingots, I use a very dry house brick with a cavity. Second time you melt it use some flux and make yer balls.
When friends learn that you cast your own bulets and ball you soon get regular donations of the stuff so I dont pay a penny and have close on a hundredweight of the stuff. I also sieve the sand trap at my club for a harder alloy for .357 bullets.
“If a cricketer, for instance, suddenly decided to go into a school and batter a lot of people to death with a cricket bat, which he could do very easily, I mean, are you going to ban cricket bats?” :- Prince Philip said after Dunblane