OK, I found out that bone is not actually a valid item token, I tried toying around with CORPSEPIECE and the [USE_ANY_BONE] token, or whatever it's actually called, and I still have no success. Although I did end up with bolts that used nervous tissue and hooves as components.
Once I get bone bolts working, I will be officially finished with testing, and will release my results to you all to test it yourselves.
There are now a TON of reactions for this, I made both bodkin and flared tips, and because there is no reageant token to only select weapon-grade metals, I had to make a custom reaction for every single vanilla DF metal that supports ammo production, including silver, for both bodkin heads and flared heads.
Due to this large number of reactions, It cluttered up the craftshop's screen, so I made a custom building that all of the new ammo production will take place in. It needs a fire-safe build material, because arrowheads still need fuel.
However, each bar of metal will produce 4 stacks of 25 arrowheads, so 4 times as much ammo for the cost of metal and fuel, which seems fair to me because crossbows are no longer overpowering.