Ya know i noticed that a while back too with TBP. I know i was using a 3.6.10 build but it was pretty random when the main beams wouldn't fire. I didn't change any orders or anything and i gave each ship their own beam free after warp in. it *may* have something to do with AI level. One thing i would notice too is some times they would power up but never fire, like maybe the firing arc is too narrow if its the fixed guns. But if i recall, every ship that had a moving turret would fire ok. Like the excalibur, always had a hell uva time to get its primaries to fire but the moving turrets always worked.