I got a mould made from this bloke called jeff tanner,his web site is

http://www.jt-bullet-moulds.co.uk/

He made all sorts of ball moulds to suit muzzle loading.

Best to email him of your requirement.

One have to be very careful when handling molten lead, be sure not to breathe in the fume when casting.

Shooting lead ball is a hit and miss affair however fun too.