I'm sorry to say, but I don't think it actually works. Mine is only level one (since it's legendary), but I have tried holding one and following the enemies through the whole track, and it doesn't work. If I'm not wrong, then at level one is shoots around once every ten seconds, which is too long to do anything. If you could upgrade it enough, it might work, but as is it's basically worthless (As far as I know).