Ed, the first thing you need to do is slug your barrel. The reason is, the groove/bore diameter varies a lot between different manufacturers, especially in the old original rifles (depending on who/when it was made, the groove dia. could be anywhere from .375 to .380). Proper bullet fit is essential to accuracy in cast bullets, and if you know the bore/groove measurements, and rate of rifling twist, your choices will be a lot more clear.
That said, I have a good shooting bullet that I use in my .38-55 that was bored for me by Dan at Mountain Molds.
http://mountainmolds.com/Good luck, those .38's shoot great, and are a lot of fun when you get the right bullet sorted out.
Greg