ThisisMyBoomstick: There is no secret formula (or secret handshake), when it comes to bullet casting. The process is actually pretty simple.
Would likely take up far more space than reasonable on this forum, to explain all the ins and outs of bullet casting. If you wish to get a more thorough breakdown of the process... feel free to pm me. I've been bullet casting for quite some time. Fifty-plus...Closing in on 60 years now. So have some idea how it's done.
DancesWithEmptyCases, is clearly a well experienced bullet caster. Whose knowledge would also be of great benefit. I'll bet picking his brain, would go a long way, too. SniderShooter is another highly experienced bullet caster. There are likely more on this forum, who might also pitch in.
For an even better resource:
Pick up a copy of the : Lyman Cast Bullet Handbook. An indispensable resource that explains the entire casting process, in great detail. Great for bullet casters, at all levels. Highly recommended.
Purchase a copy of the Handbook, before anything else. Read it thoroughly. Then, think about the equipment that best suits your needs.
Since you were showing an interest in shotgunning, ordinary wheelweight lead will do the trick for most applications.. If you can make your own shot...the sky is the limit, if wanting to try harder alloy mixes, etc. As noted, slug and pellet molds are also readily available.
Lee makes some good ones. Be sure to check out Lee Precision, for a good sampling of bullet casting molds, casting equipment, etc. There are other sources, but....Lee's very inexpensively priced molds, etc., are a good place to start. I use them, all the time.
Hope this info is useful
Al