In the Seal spawn go up in the building in the middle of the spawn. Go up to the top jump onto the ledge that is facing the door, once on it face the right side of the spawn so your body is left to the door. Go prone once your prone start going left like your gonna fall off, just till your body is half on half off. Then lean left with the D-Pad button, as your falling reload your weapon, but keep holding left once your gun reloads let go of the reload button but still hold left button you should fall and sink under the map. Once under you still have to hold left but you can move your right analog and shoot. Very good if you have a scope.