I believe I know exactly what you're problem is, more and more people seem to be having this problem. Ok, when you put the actuator on the joystick, push it up so that that metal thing it rests on is being pushed up into the joystick shaft, don't worry, this won't hurt it at all, it's how it was meant to be put on. When you do that it should fit perfectly, and move around with any problems.
-Good luck
-CthulhuLuke