I have done my best to find answers to this question, but I can't seem to find anything particularly convincing.
I have been playing for quite a while now, and have yet to understand exactly how hit points work. In actual game play in STF's for example, the hit points of a purple MKXII anitiproton cannon with beam overload III (with weapon power at 125, 4 mag regulators) has ranged from 400 to 30000. Hit points from dual heavy cannons of similar mark seem to range from the teens up to the thousands.
The only part that seems to be consistent is that if when the ship comes into the 10km firing range, I fire an overloaded beam immediately, the hit points are very low. Apart from that, I cannot seem to work out the logic behind it. I know that there is an increase in hit points the closer you are to the target, but even this seems somewhat random.
Finally, in PvP, the hit points I achieve almost always seem to be lower than in PvE.
I'd be most grateful if anyone who knows how it actually works could chime in - what determines the hit points on each occasion that you fire, other than weapon type/grade, range, weapon power, target resistance, and critical vs. non critical hit?