[KrazyCarl92]

Originally Posted by Alan Anderson

If you can deal with the turret having a limited range of motion, your "sprocket" can be a wooden disk with chain bolted to the outer edge and driven by a smaller sprocket. You can either have the chain make a typical loop around the driving sprocket, or just have the chain in a circle around the disk and drive it as if it were a gear.

If I am understanding correctly what it is that Alan is suggesting, you could also apply a torsion spring to the axis of the large wooden disk, wrap the chain around almost the entire disk and come up with other creative ideas to get close to 360 degrees of motion.