Cast or swaged? I have been casting bullets since I was 14 (55 years ago), casting .22 bullets is very difficult.
I have found cast bullets rewarding. I have shot them in competition out to 600 yards. In airguns I have cast for and shot 9mm air rifles with good results. This was when the only 9mm pellets were Koren. Casting is very time consuming and a little dangerous. Also molds are usually set up for firearm barrels, which can have different dimensions. Swaging looks like a better alternative. Either way, I think my money and time is better spent on pellets and shooting.
BUT
Pellets have an upper limit for velocity, and if you plan to seriously exceed those limits, then molds and sizing dies are in your future.
Ron