Indeed they do shoot fine - the issue is when you are evading or even maneuvering to attack, there are roll/pitch rate and roll/pitch angle limits that simulate it being difficult for the gunner to aim as you fling your craft over the sky and its at steep angles or rapid rates of change - as it would be in real life.
The AI pilots are trained to keep their craft as steady as possible to ensure maximum rear gunner efficiency.
Players should bear this in mind - imagine trying to shoot a target as the craft is flung all over the sky by your pilot. There is also a steadying time involved.

I will look and see if they are reasonable and adjust if deemed necessary but again not promising when or even if I will change them - I will look at them though.
Remember changing these limits will make your gunner fire under difficult circumstances (and make you feel safer) but will he hit anything? probably not - as in real life.

Note again that the all craft, AI and player, are subject to these limitations - the AI fly EXACTLY the same craft with exactly the same limitations as the Player.


HTH

WM