For many years ... I have done alot of shooting and plinking with a roundball loaded in a primed cartridge case with a small amount of powder. They were a great joy to shoot in a bullet trap. We found them to be so accurate, I have put out the flame of a candle without hitting the candle !! It seems if you have a .500 S&W, you pretty much stuck shooting only earth shattering loads. On Ebay is this old dixie mould: --Vintage Dixie Round Ball Mold Pliers 505-- It is a .505 roundball mould, perfect for the .500 S&W. The round ball can be run through your sizer and can be crimped into the end of the shell. A small load of maybe 5 grains of red dot or unique, and some kapok on top of the powder (between the powder and the ball), you would have a very pleasant plinking load you could shoot all day at small targets or field targets. If you worry about leading, roll the ball in Lee Alox and let dry. Small loads like this put almost no strain on your brass cases and you can load them many, many times with these easy shooting loads.
Just saying there is a way to really enjoy shooting your monster caliber pistol without loads that measure 9.5 on the Richter scale every time you pull the trigger. Even your children would enjoy shooting these round ball loads.
Ohio Rusty ><>