I would recommend turning them as the best way for simplicity sake as well as cheapest considering how much you are likely going to shoot it, though getting a custom press die for copper jackets then casting lead into it and pressing it to size would also work. It all depends on what exactly your looking for.

Any shop with a CNC lathe could likely pump out some brass bullets quickly, the only thing being they might not like the idea of making bullets as to the potential liability of it (i.e. a couple thou can make a big difference in pressure). These bullets would also be lighter than the originals for the same length so that is also a factor.