a friend of mine used a smokeless pmc 45-70 in it, but don't know what kind of powder they use. i know he gets alot of info from Culvers...
you should go to the reloading section of the culvers shooting pages
[
Http://www.jouster.com/ ] and I'll bet someone there knows. i remember him saying you make case from the .348 case for the .43 spanish. Sorry couldn't be of more help .