The lead in jacketed bullets is going to be soft so plan on hardening it somehow. Adding chilled lead shot is an easy way to harden it some. It doesn't take much, a small handful for a 20 LB pot.
Wheelweights are easier but becoming more scarce. Pieces of old lead drain lines found in crawl spaces are a good find but again, will need to be hardened for most uses as it is pure soft lead.
Start reading about lead alloys and scrounge every bit of lead and ww's you can.