I picked one up years back, but it was a bolt action. I bought it at a flea market and thought it was a BB gun at first glance. It would be wise to use CB caps only. I don't know what yours has stamped on it, but mine said ".22 Short only". Maybe why you had problems inserting a .22? The barrels were brass, but not solid bar stock. It is an insert of rolled sheet brass stuck inside a steel tube. I believe they rolled the sheet around a mandrel and pressed it at the same time because mine was rifled. It may have been designed for black powder, so be careful. Nice job on the restore.