Not to sidetrack you, but you might also consider a front stuffer if you want something in an eight or four bore. It will cost you a LOT less and the cloud generating BOOM is every bit as satisfying. Further, while I do love the vintage weaponry, with this option you are able to build YOUR rifle rather than purchase some dead guy's idea of a perfect elephant rifle.

http://gefrohbigbores.com/

Best,

John