I believe Jeff Tanner moulds would suit you, they are brass and can be made to your specs much less than 125.00 I think they fit lee and lyman handles. They are made in England. I have a lee mould in 60 cal I have yet to cast any balls for my green mountain IBS barrel in 62 cal but they say it is a 61 actually I bought some cast round balls in 60 cal and they were tight with a thin patch I hope the lee mould will throw a good size ball for the barrel. you can measure your bore and know for sure what you need. I saw in your post you said 60 cal if you indeed have a 60 cal would a .575 mould do? A lot of people who shoot tc 56 cal smoothbores use 535 rb with excellent results? just a thought.