You're welcome. I needed the feature myself, so I searched and found a Podpathos capx
that demonstrated limited fields of fire, but implemented the turret directly in events rather than using the behavior. I wanted to have predictive aim, firing rate, etc, from the behavior, so I modified it to use the behavior and still limit the field of fire.
To demonstrate the effect of turning Predictive Aim off, I updated the latest version of the capx above to set Predictive Aim off on the third turret from the left. For this pattern of targets, and the velocities involved, it never hits a target, ever. I also added field of fire indicators to the range indicator when you click on a turret.
I think limited fields of fire is the only really needed thing missing from the turret behavior. Perhaps an option to limit the detection area to the limited field of fire as well. Also, having a detection range that is longer than firing range might be nice, since you can almost always see the target before it is in range. But that can easily be implemented in this capx by simply setting the bullet.range at time of spawn to something like turret.range * 0.5, and then doubling the turret range. The problem of detecting enemies behind turret, outside of the field of fire, would still remain, and be made worse as well. This is bad because the turret locks on to the first target in range in my preferred targeting mode. So for some time it may be unable to fire on the current target, while other targets pass within its field of fire. The solution is probably to monitor the diffangle and distance to the target, and as long the current target is out of range of the actual bullets, force it to unacquire the target (a feature of the behavior), say once a second. Then the turret will re-pick the nearest target, which could be the same target somewhere behind it or out of bullet.range, but at least there is a chance it will re-target something in front of it that is in range. The downside to not permitting the turret to target beyond the field of fire and range of its bullets is that you lose the opportunity to pre-rotate toward the target, which allows it to get more bullets on the target depending on the circumstances. I think most games just allow the turrets to rotate really fast to solve that issue.