Armoured Train Machine Gun Turrets

I've been fiddling around with the turrets for the machine gun wagon this evening, using various bricks to form the cupola, a flight stand as the top and plastic card to cover over inconvenient holes and to create the deflectors, which you always see in pictures of this sort of thing. I cheated with the machine gun barrels and used some cut-down Brigade Games metal Vickers HMG's that I bought in a Northstar sale when they were going for £2.50 a pack. I still have some bits to finish off but I think it looks OK so far.