I have pounded bullets out with just about every material listed above.
When you are pounding bullets out, you come to appreciate the virtue of shooting lead. Jacketed bullets that make it very far at all into the barrel are an absolute b**ch.
My advice on the various methods to dislodge a bullet is to perfect your process so you never have to find out how much pounding the various materials will withstand, it is not fun.
When asked what qualities he most valued in his generals, Napoleon said, "give me lucky ones."