So this is not entirely true. There was lead in the water, but not simply because of the lead pipes. The Federal emergency manager assigned to flint to tackle their financial insolvency decided to stop buying water (clean and safe) from the city of Detroit, and just pump city water out of the Detroit river instead. Now the Detroit river is a toxic pit of industrial disgusting if I have ever seen one. Step two in really screwing this up was (as another cost savings) they stopped putting corrosion inhibitor in the water, who knows what consuming corrosion inhibitor does to you but that is another tangent. So we have corrosive Detroit river water attacking old oxidized lead pipes which before now caused no trouble and dumping the product into your sink. Not the fault of lead. If I had to point fingers it would be the emergency manager.... now where was that bucket of tar and bag of feathers...
But back on topic, The REAL is designed to have the skirt flair and fill the bore upon firing right? I don't see that happening with anything other than soft lead. If you absolutely have to use non toxic and want to cast, try casting a round ball and patching it, I honestly think it is the only way you are going to get it down the barrel.