Which should I go wth carbide or regular dies for 500 S&W?
TIA

If you have a choice, always buy carbide. Life is too short, just makes loading that much easier.

Definitely, get carbide but you may still want to use a little lube even with carbide dies with such a big case. I like Imperial Sizing Wax best for lubing cases.

The carbide is the way to go. But lube is still a good idea. The carbide ring is very very thin on the 500 dies. I have broke both a lee and hornady carbide 500 die.