If a ship has identical primary weapons with different fireArcs (say, one on the port side and one on the starboard side), the AI should select whichever weapon has its target in that fireArc. Currently, it will stubbornly keep facing the same weapon at its target to the best of its capability.
(Song: Yes, I know you have issues with weapon selection by the AI. Make your own ticket about those. ^.~ )
For clarification:
Setting a weapon pointing to the side (minFireArc and maxFireArc set to a small swivel (or both set to either 90 or 270) enables a broadside style of combat with the other weapons set as secondary weapons. (Alternately — and this is what I’m actually doing — creating a virtual dummy weapon (no fire effect or sound, and an <OnFireWeapon> event that returns true) while setting the real weapons as secondaries will accomplish the same thing while allowing all weapons on both sides to make attacks against targets of opportunity.) Setting an identical weapon on either side as a primary should enable the ship to rotate which ever side is closer toward the target and pick the appropriate weapon as its selected primary weapon. This is not the current behavior.
The point of the ticket is to allow ships to be able to switch which weapon is currently active based on which direction would entail less rotation to bring it to bear on the target. This is particularly significant for a larger and more sluggish broadside-focused ship. You don’t want to have to rotate through 150° in one direction to get your weapons on target when you can just rotate 30° the other direction and have an identical set of weapons on target. Since the AI already knows which way to turn to get weapons on target, it should be able to check to see if one weapon direction is more advantageous (read, closer to on target) than the other, particularly in the case of otherwise identical primary weapons.