When was the barrel made? If the barrel is original to the frame, and came that way from the factory, you can tell from the serial number (check the FAQ's). It could be an earlier .44 Mag with an oversize bore, if so you may have to handload larger diameter bullets. Others have discussed that quite a bit here....<><....
And by the way, welcome aboard, this is the place to be for in on, or just to discuss, Handi's. When you are here you are among friends....<><....