Also on the turret problem make shore the wires are not getting hung up I use plastic ties to keep them grouped together if you had the Pershing the hull is cramped so you have to use good wire management .
I have also used lithium grease on the bottom of the turret it helps if you have the King Tiger or the JS2 you may need some more weight in the back of the turret to off set the heavy Barrel pulling front off turret down .

Jimmy