I thought something like that was going on. That's pretty resourceful.
That only covers half the available races, though. What do you do about the male races?
And yeah, they could be real bullets. I think the most detail they went into was them "using photons to fire bullets" or something. I assumed they supercondensed the photons into nearly solid projectiles, but it could just as easily be explained by them being given enough bullets to last them the mission (stored in hyperspace?). Your version makes for more drama too.
