Galleryless piston with slotted ring groove

A method of manufacturing a piston, comprising the steps of:

• providing a body including an upper wall, the upper wall including an undercrown surface exposed from an underside of the piston, a ring belt depending from the upper wall and extending circumferentially around a center axis of the piston, the ring belt including a plurality of ring grooves extending circumferentially around the center axis and each formed by an uppermost wall and a lower wall spaced from one another by a back wall, a pair of pin bosses depending from the upper wall, a pair of skirt panels depending from the ring belt and coupled to the pin bosses by struts, an inner undercrown region extending along the undercrown surface and surrounded by the skirt panels and the struts and the pin bosses, a pair of outer pockets extending along the undercrown surface, each outer pocket being surrounded by a portion of the ring belt and one of the pin bosses and the struts coupling the one pin boss to the skirt panels, and
• forming an oil drain slot extending through the back wall of one of the ring grooves to at least one of the outer pockets.