What kind of a crucible do you use for the melt?Good question, and I'm happy that you used that term. Not many people understand it these days. A crucible is a pot that's used to melt metal to prepare the metal from a raw state to a more finished product. Many people use the more modern term "lead pot", but I was taught to use the term "crucible".
Lead comes in many forms to the observant caster. I'm always on the lookout for raw lead, whether it be in the form of roof flashing, old plumbing pipe, expended linotype, plumbers metal, naval ballast, or any other type of lead-based material. Raw lead bullet material is bulky and has to be cleaned and rendered to a more useable configuration.
I guess we should begin this discussion with one important caveat. Once a vessel or implement is used for processing lead, it can never again be used for food. I keep my lead cleaning implements separate from my food processing implements and never the twain shall meet. Don't risk lead poisoning from mixing implements.
I've got two pots I use for cleaning metal. The first is a big ole pressure cooker that I found at a garage sale. The second is a smaller plumbers pot that I picked up years ago. I select a pot and put it on a backyard propane burner, the same burner I use for frying fish and turkeys. I put big pieces of plumbing metal, or large quantities of wheel weights into that pot and turn on the burner. When the metal is melted, I skim the impurities and put the cleaned metal into molds for ingots. I've got three different molds that I use to process lead. They cast ingots in different configurations so that I can know immediately what alloy I'm using. Almost anything can be used to convert raw lead into ingots. I prefer having three ingot styles. The first is a conventional rectangular ingot that I use for soft lead. The second is an old cornbread stick pan that I use for wheelweight metal. The third is a weird old cast iron cooking mold that I use for linotype ingots. With those three I can look in my lead supply and visually identify the metal type depending on the kind of bullet I want to cast.
I've seen some guys use muffin tins for converting raw lead into ingots. Round, square, star-shaped, you're only limited by your imagination. You can pick up lead smelting implements at garage sales if you keep a sharp eye out. I've been collecting mine over a lifetime. This stuff normally doesn't wear out.
Once I've got the raw metal converted to ingots, I use a Lee Production Pot for actual bullet casting. It's a bottom pour pot that uses household electricity to melt the metal. I've had this particular pot for twenty years and I've gotten used to it's foibles. I like using an electric pot for the actual bullet casting because I don't have to stand over a propane cooker while I'm casting bullets.
Lots of folks make bullet casting furnaces. The big discussion among bullet casters is which is best. Some maintain that an old style dipper is best for filling a mold. Probably the most traditional way to cast a bullet is to use a Lyman Lead Dipper and fill the mold from the dipper. Millions of bullets have been cast using this method and lots of folks prefer it today. Others of us like the bottom pour pots. Either way works. Both have their adherents.