I thought Black Powder scopes might have some provisions to make them more suited to the "dirtier" environment associated with black powder shooting.
Not really and that is one reason they sell those rubber protectors to keep the underside of the scope from accumulating any residue. Now, they do make armored scopes but that is a separate issue and not related to being used on M/L's. One still has to clean the underside of the scope.
Be Safe !!!