That looks like an old jig from the Ament company. There's one on ebay right now that looks like it:
Ament jig mold Do it yourshelf - eBay (item 170422300029 end time Dec-26-09 18:08:31 PST)
No. 284 AMENT JIG MOLD SINKER INDEPENDENCE MISSOURI - eBay (item 250552162184 end time Dec-28-09 15:59:24 PST)
If you can't find it check with grousefly he seems to have every mold there is LOL.
Fatman