Nice roller Dave. I bought one just like it years ago but in far worse exterior shape. The bore was excellent shape but I couldn't find any brass to load up and so re barreled it with a Numrich Arms "Creedmore" barrel. Half round half octagon and chambered for 45-70. it was a real hoot to shoot. Unfortunately, I sold it off shortly after getting married. It's the only gun I've regretted selling. Still have the gal though. She's a keeper.
By the way, I don't think your"s is an Argentine model. Those rifles has a short, about 2 to3" octagon profile at the breach end of the barrel, making them the nicest looking of all the rolling block military rifles. It's still a pretty nice looking gun.
You should be able to find a set of dies and a bullet mold for it on Ebay or elsewhere. And brass is available, though expensive, and would be a better option than reforming scarce and nearly as pricey 348 Win.

John