The adjustment screw is located on the top rear of the trigger housing. To lighten the trigger, use the supplied 5/64" Allen key and turn the screw counterclockwise. The screw can be safely removed, at which point the trigger will be at its lowest pull weight. To increase the pull weight, use the supplied Allen key and turn the screw clockwise. The trigger is designed to lock out if overtightened in order to protect it from damage.