Unfortunately you can only get sheet lead in sizes suitable for birdshot, and biting out pellets at the rate of 200 per ounce is a bit much. It wouldn't be a hard alloy either. What I tried was slabs cast by myself. That mould for six inches of quarter-inch rod sounds very workable, for any kind of swager. It sounds a lot more likely to work consistently than a mould for a long string of tiny balls.
I'm just guessing, but I think commercial swaging of large pellets from lead wire probably involves two wheels with edge to edge hemispherical depressions. If they are kept in synch with gears further along their axes, that ought to work. For the class act, see eBay and search for "rolling mill" under "jewellery". It is the sort of thing that could be copied quite a bit more cheaply than you see them there.
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