There is absolutely nothing wrong with Pyrodex pellets or Pyrodex RS. Pyrodex is a very good and consistent powder: i used Pyrodex exclusively for years and killed a lot of game with it. Pyrodex is the most inexpensive powder available.

In my guns two Pyrodex pellets and 100 grains of Pyrodex RS shoots to the same point of aim. When hunting my gun was loaded at home with loose powder and my reloads were pellets. 777 is also a very good powder, never used 777 pellets and can't speak to them.

i've never used BH209 and likely never will. Some friends who tried BH 209 went back to Pyrodex and 777. Go ahead and use Pyrodex: Just clean your gun soon after shooting.