GOW3 campaign mode - silverback turret spins, doesnt fire!?

hi, i opened the door with the levelr controller, got in a silverback, walked up, kicked thru the gate, the large monster leviathon starts biting the ship deck, im supposed to use the silverback turret to shoot out the eyes, and its not firing bullets?, i see it spinning, but not gunfire?
tried, going back to level beginning, tried different controller, tried other silverback, tried looking online youtube vids...?help?
thanks
m

I know which part you mean and that's a really unusual problem you got there! Only thing I can think of is there is something wrong with the disc since you already tried everything you could possible try (or what I would try).

You can try borrowing it from a friend or renting it and try that part on another disc to see if that cures it at least then you know what the problem is. Other than that you will have to do that part without the COG Silverback