Answer to sparklerfish:
Fire stacks on guns can be prevented or dealt with heatsink ammo(as a temporary solution until an engineer extinguishes the fire), as a gunner you can do that much when you know there will be a lot of fire dealt from the enemy side.
Well, once a gun is overheated, you can't load heatsink. It would be neat, actually, if you could reload a gun with heatsink while it was overheated and slowly eliminate fire stacks to make it usable again...