it adds(wound out) and lessens (wound in) the amount of air stored in the dump chamber. if it is would all the way out you get a slightly quieter shot but if you wind in all the way in you get a bit better efficiency
Hey! You with the face! And the Nose! And the Mouth! And the Eyes! I KNOW YOU.
The whole reason we help players that are new to the sport is that they continue to play the sport and make us look better than we really are