Have you ever tried a Lyman M-die? I use them for almost all my lead bullet loading now. In an auto indexing shell plate they also help hold the bullet striaght up as the case moves to the seating die. They also greatly help with being able to set a flat based bullet in the case without fumbling around. This is a pic of a .357 with the case mouth expanded by a Lyman M-die:
Notice how the case mouth is expanded just enough to not shave lead (or in my case the coating) and the bullet is striaght up and not setting at an angle.