You can only adjust the pull weight and over travel. After you break the locking nuts loose adjusting the screw in and out sets the over travel and the nuts away from the spring sets the pull weight. DO NOT adjust a factory trigger to less than 3#. To test the trigger close the bolt rapidly as if speed loading (push the bolt closed and turn the bolt handle down as if your hand works the bolt in one quick motion). If the firing pin falls you need more pull weight.