It is a temperature type of thing. I use a Colman stove and a old cast iron pot to melt the lead in. Then the first few bullets that you make you dump back into the melting pot, they are just to warm up the mold. Then once you get to where you are getting clean shinny bullets with no lines or cracks in them that you can see you are good to go. I use a old towel to drop my cast bullets onto to help keep them from getting damaged.
To get started you would need a stove to set up outside, some mold handles, and a ladle to dip into the molten lead to poor into the mold.
But it is like everything where you are working with something that is very hot you have to be extra careful or you will get some good burns on whatever the lead gets on.
On the Hornady bullet, you can do some searches and see if you can find a mold that replicates it. It is too bad that the .54 caliber muzzle loaders are going away, it is a great caliber and packs as punch. I actually purchased a .50 caliber barrel to go onto my TC Renegade's stock just because .50 caliber bullets were so common.