Currently, the bullet casting technology appears in the technology tree before the metallurgic science pack technology is unlocked. Ideally, since it requires those packs to research, it would have it as a perquisite.
This would require adding "metallurgic-science-pack" to "technology/efficient-bullet-casting.lua" alongside "military-3"
Assuming there is agreement about this, I'd be happy to file a PR to help, but I appear to be unable to make an account or fork the repository or anything like that