Some die sets (such as Dillon, Hornady) come with a seater die that includes either a flippable seater plug (Ex: Dillon) or two seater plugs (Ex: Hornady). These plugs are optimized for flat point designs, and for round nose designs respectively. The Lee seater dies work with both bullet profiles, but may not seat as consistently in some circumstances. (correct me if I'm wrong but I think it's a one-size-fits all seater with the Lee dies).