The new "cowboy" loads are only for making huge steel targets a foot and a half from the firing line go "plink" as quickly as possible. They are strictly for entertaining accountants who decided to wear chaps and name themselves Buckshot Billy.
The old loads were not for games, they were for hunting and SD, and were loaded for those purposes. They had no use for cases full of cornmeal, the brass for the old calibers is large because they had to be big to hold as much blackpowder as they wanted (a lot).