Take the stock off.. There is a screw located under the trigger bar. You have to pull the trigger bar off and you will see it directly below. I think it's a 2.5mm allen screw. If memory serves right hand turn is less sear engagement and left hand is more. Be careful though as there is a little o-ring under this screw to add some tension but if you unscrew it too much it will work it's way out.