HW110 Drain the Air from the Cylinder

Cock the gun, engage the safety lever by pushing the safety lever forward/own so that the red spot is covered.  Then, on the right hand side where the safety lever WAS, you will see a small hole... 

Put a 2.5mm allen key down there, you may need to wiggle it around a bit for the allen key to engage/get into place, it is at a funny angle, it's not straight on, then screw the allen key clockwise 3 or 4 turns (to empty).   Once emptied, turn the allen key anti-clockwise the same amount of turns to close the air release valve and then disengage the safety, fire the gun to release the hammer.