Flash 6 making script animation smooth

1

I made an animation with actionscript, but i does not play smoothly.
I cant use "smooth" cause i have to use flash player 6. i increased my frame rate, but it didnt change much.


onEnterFrame = function(){
		 		 		 if(_rotation >= 13) {
		 		 		 		 _rotation -= 40;
		 		 		 } else {
		 		 		 		 _rotation += 0.22;
		 		 		 }
		 		 		 trace(_rotation);
		 		 }
		 }

help me please.
any idea is welcome.