Charles-

In about late '94 S&W switched to EDM type rifling. It isn't realy any shallower, it is different in that the edges of the lands are slightly rounded, especially in relationship to the older cut rifling.

25-2's for sure, had shallower rifling than other S&W's, and came in a 6 groove configuration as opposed to the standard 5 groove of most S&W's. I don't own a 625, but I have read many time that they have the shallow rifling as well. Maybe someone who has both can speak up here and set the record straight.

Cast bullets will shoot fine in shallow rifling, IF they are cast fairly hard so they can hold the rifling and not skid, ruining accuracy and causing leading.