Capital ships not using all their weapons is a major weakness of the combat engine. They do not consider targeting sometimes when performing other actions (such as moving, or even during attacking a target manually). Pressing "stop" or clicking to attack a target causes a volley to be fired, showing that certain weapons have been randomly idle but could have been firing. The autocannon is probablly the most reliable weapon to autotarget, but it should focus on a manually selected target like all the others (you just can't control it!). When not manually attacking, all weapons should prioritize and focus on threats. Targeting should be updated with each "tick" (when the resource amounts update, about twice per second) to keep weapons "hot".