For the life of me i don't understand why you need lead except for trying to kill something. You mean to tell me slingshot shooting can't be fun or accurate without using lead?????
I don't think that was ZDP's intent. He's merely wondering about and experimenting with different alternatives. As he said, "Each to his own according to the circumstances." I have tried steel and lead in several sizes, as well as marbles of various types and even some loose Hornady 10mm XTP 180 grain hollow points that I had on hand. I shoot 3/8" steel 90% of the time and am perfectly happy with it. My lead (.454" ball) ammo (except a small amount I practice with) is reserved for hunting purposes. So, I guess we sorta agree.
But there's nothing wrong with experimenting with alternatives.