Thanks you two, it appears new revolvers are .451, but I'll check the particular revolver involved to verify. It explains to me why suppliers are offering primarily .451 & .452 currently. And as far as Todd being an expert, as old as you are Todd you have to be an expert in something, so lets go with the firearms field, I don't want my mind to go wondering!
However, it still doesn't totally explain why the various loading manuals handle this the way they do. Reloaders literally put their lives in the suppliers hands. Take care boys and Merry Christmas!