Bud of mine came up with a couple of boxes of those. After shooting them all up, he went on a serious hunt for a mold. They worked out really well. He's a dedicated fox hunter and the mini's greatly extended his range compared to round ball. Foxes aren't hard to kill, but you have to hit them first.
Don't recall his powder charge, but as with so many other rifles and calibers, best accuracy occurred when he put a lubed felt wad between the bullet base and the powder.