Some context for the GDI APC gun, which is still in concept stages.
It is most likely going to be an auto cannon weapon, something no TSR unit has right now.
Damage-wise it will be worse at anti-infantry than the Wolverine, and worst against vehicles and structures than the Titan. It would be a sort of "sub-par jack of all trades, master of nothing". Useful to help finish off low health enemies, but mainly to help make the driver have something to do while driving. It's also a decent tool for communication; Being able to fire upon the intended target so the crew knows, without having to directly communicate, what the intended target is.
Being an auto cannon, it would mean it has a relatively low RPM (something like 1 round per 0.75 seconds, give or take).