I have seen a number of threads about Roman guns, which I don't think possible but it got me thinking. If gun powder had been discovered, and I can see no reason why it couldn't I could see the use of rockets and catapolts lobing primitive bombs. I have also seen a documentry showing the discovery of what was interpreted as part of a hand held balister, at a Roman garrison sight in Germany. This would in my opinion be both too heavy and fragile for use. My theory is it was part of a model in the C.O's office or a prototype. If it was a prototype I could see it been developed into a more conventional crossbow. Now if these weapons had been put into wide spread service could the Empire have survived longer in the west. A competant crossbow man could be trained in a few weeks square bashing which would ease the man power situation, and could allow for more effective local militias easing the demands on the legions. The use of rockets and gun powder bombs would at least initialy terify the germanic tribes. Also a legion drawn up in three ranks shooting off controled vollies and supported by rocket fire and cavelry is going to ruin anyones day.