You want to convert NERF darts to be safe in a foam-fighting boffer game? Don't use a titan. Mission accomplished.
Edit: Aha.. didn't notice you guys use a 2.5 inch rule, too.. you're essentially trying to make Crossbows more viable to use? Good luck with that. That said, there was a post a good while back about a crossbow out of a Nitefinder.. I recently made a very rough replica of Van Helsing's repeating crossbow by just adding some stuff to a Mav. Performs like a Mav, but.. you know. Looks like a crossbow. *shrug*