Now you can play Fieldrunners in Real! :-P
This is the basic Turret of Fieldrunners (Game for iPhone and iPad..).
The turret can be rotate 360° like in the Game. The diameter of the "Blue Ball" is 5cm. I prefer to print it with WS&F and colorize it by hand.
I have cut out the 5cm one inner sliding, i updated the 3D file for both so it should be easier to sap the parts together. For better rotation you should polish the sliding surface with sandpaper or order the polished one, don't know if the small one can be ordered polished because its very thin..