MAMBA ballast casting mould
thingiverse
print it (the finer the better, 0,2 works good) and cast it in a high temperature silicone. You should be able to cast 12 MAMBA ballast pieces from lead in a single step. Its a bit tricky to get them out of the frame, but as long as they are heavy they work just fine :) Maybe there will be a version #2, which contains better canals to spread the lead more evenly.
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