if +activateturrets is on, you can see the power bar drop for charging but it doesnt fire unless you turn and face the target.

This causes the turret to miss much of the time as the angle wont be correct
It also wont fire again unless you move your field of view off the target and back on.

Uh...actually the rep turret charges while AT is on, then fires when it's turned off, then charges when turned on again and so on.

if you turn your ship (not the turret) and face the target, it'll shoot.