Recently I had some trouble expanding some once fired .32 Auto brass with the Lee flare die. The bottom of the expander plug would catch the edge of the case mouth and peel it down like a banana. The remedy was simple, create a taper on the bottom of the expander plug so that the plug would guide itself in to the case mouth without catching. I just used my bench grinder to do this and now it works great. I'll likely try the same thing with my 9X19 flare die.