If you have lead, you can cast your cores. There was a video showing just that.
I spent a few hours watching videos on the whole process. I saw people using the Corbin press which is built like a tank, prople using RCBS and even LEE press. I watched them using 22LR spent cases to make .223, using preformed caps, or just a copper sheet, punching out discks and turning them into cups, jackets.
It is very interesting, however at my age, the entry level cost is prohibitive for the amount of bullets I see me using beyond of what I have.