On the Rapid Re-forcement resin armoured vehicles, the turrets come separately but are not attached to the hull. Bit of a nuisance however, thanks to a tip off from my son, who uses rare earth magnets on his 40K collection, there is a solution.
An appropriately sized hole is drilled into hull & turret & magnet is superglued in. Be careful to get the polarity right!
The result is the turret does not easily come off and is able to "rotate" with ease to face enemies.
I hope this is a useful tip.
donald