I'll say. You could throw it in and go work as a coal-miner, but then you'd have to worry about the coal you mined being used to smelt steel that goes on to be manufactured as bomb casings. And so on. Certainly you shouldn't work on anything that offends you conscience, but the mere fact that something can be repurposed for warfare doesn't create moral responsibility.

This isn't to say that worrying about war or your personal purpose is misplaced GH Hardy opined that ballistics was 'repulsive' both because of the moral purpose and the triviality of the mathematics involved, and there are more musings on the ethics of that sub-branch of math here: http://www.augustana.ualberta.ca/~hackw/mp480/exhibit/ballis...

But as long as you're knowingly working on some sort of combat system, it's folly to beat yourself up over the limitations of foreseeability and the vague possibility that something you craft might turn out to have military utility which you din't intend at the time you conceived it. Instead, look for ways to provide utility in other areas.