I agree with ATN. The best way to stop a swinging load on any length line is to move the cyclic so as to position the helicopter over the load. Although a lateral swing is the most common swing it is possible for the load to swing in any direction but this technique will work regardless of direction of movement. When done correctly the swing will stop almost immediately. The technique can be learned quickly and a little practice will give you great confidence.
Should you ever encounter a swinging load that does not respond to this technique you should jettison the load before the load swings into the aircraft or full deflection of the controls occurs. Either is bad news.