If you want to shoot cast bullets with sabots, then go to a .458 rifle bullet, the .429 pistol bullet is too small. The petals on the sabot are too thick, due to the smaller diameter .429bullet. The .458 has a thinner petal, and more bearing surface. The second thing you can do is use a softer than #2 lead mix. I usually go 25 to 1. You do not have to worry about leading, and with greater velocity you get fantastic expansion, Tom.