Looks like my Dillon powder-funnel/flaring die was originally made the 50AE caliber because that's what is stamped on the metal. I called up Dillon and they said it's the same for the 500SW.
When I tried to slide the re-sized cases (which are up tp specs), it cannot slide in easily without a moderate push. This made the case bigger than what is should be in the top 1/2 half inch or so. Ideally, I am expecting the die to slide in until it reach the mouth where resistance will start and create the small flaring at the mouth.
John Ross and other folks mentioned about polish down the flaring die. What do you suggest using to polish down a piece of steel? Sand-paper for metals?