IIRC, when the guns go down, it is because the crews are dead..
When the new owners roll in, they naturally recrew the guns..
That's what my memory says anyway..
Actually, it's just an abstraction for gameplay purposes..
I have done the old sneak in behind, and deack/retake
towns behind the advancing force.. LOVE doing that!
One of the sweetest moves in the whole game..
Drives them CRAZY!