I regret having to cool down your fantasy
.
I have meanwhile been paging
Collectors Illustrated Encyclopedia of the American Revolution, by Newmann & Kravic.
Inumerous moulds are shown there, since folding handle to ball & buck models, similar to all examples shown here.
I don't think these multi use moulds, like the one i have posted, are for double calibre guns but for casting projectiles for different weapons, depending on respective necessity. Naturaly heavy weight devices are not portable and are certainly destined to backing facilities. Whether they may considered military or civilian is a question that, being omitted by Neumann, falls into knowledged Adrian's criteria.