Gamebore load an excellent 1oz of No.6 black powder cartridge with rolled turnover and paper case. They do have US outlets that will supply anybody by mail order.
http://www.gamebore.com/game-loads.asp will take you to their website and you can contact their manager, Paul James [paul@gamebore.com] about suppliers or shipments. He is very helpful.
I also use their 65mm case, fibre wad 'Pure Gold' in all my nitro proofed guns. They are very consistent and ideal for game shooting with old guns having 2 1/2" chambers.
