If your tank gets its main gun damaged, the bow MG might still work.
To find out if the MG still works, try issuing a 'Target' area-fire order into the ground. If you get an error beep it means the MG is broken, but if the line sticks it means its working. Cancel the line and use the tank as a mobile MG pillbox for the rest of the game..
PIC 1 -This T-34 had its main gun damaged earlier and its turret is jammed in position pointing right.
An enemy squad run across the road in the background..
PIC 2 - the bow MG opens up on them and cuts them down (note the tracer, and the ammo readout drops, confirming it really is firing)
Also the MG only fires in a frontal cone, so try to keep tanks with a working bow MG pointing towards the enemy positions.
(Incidentally although the ammo readout dropped for the bow AND co-axial fire, its just a CM program quirk, the co-axial
never fired because its jammed right with the turret.)
PIC 3 - the view from the enemy side..