.454's are pretty universal in that for the most part they'll fit most .44 caliber C&B revolvers where as there are a few that may not take the .451.
Speer & Hornady are 2 brands that have been around for a long time & both make a very good product,
This guy has the best prices around IMO on purchasing Cast Balls/Bullets.
+1. For store bought balls - I much prefer the Horandy swaged roundballs over the Speer variety. bpstuff has good balls at a great price & quick delivery. His wads a pretty nice too.
Fingers (Show Me MO smoke) McGee - AKA Man of Many Colts - Alter ego of Diabolical Ken; SASS Regulator 28564-L-TG; Rangemaster and stage writer extraordinaire; Frontiersman, Pistoleer, NRA Endowment Life, NMLRA, SAF, CCRKBA, STORM 327, SV115; Charter member, Central Ozarks Western Shooters
Cynic: A blackguard whose faulty vision see things as they are, not as they should be. Ambrose Bierce