Another thing to remember, is that NPCs use some turrets that players cant.
Theres a Liberty BS Turret that has 2 barrels, fires two shots at once.
You can see it on the Missouri.
Theres a Rheinland BS Turret that has 3 barrels, firing three shots at once.
Iv not bothered with Rheinland too much so im not sure if an NPC ship has em.
(More than likely you'll see them on bases and not Patrols)