An apparatus and method for injection molding of molded products including a first cavity chamber for forming a seal liner, with the first cavity chamber having an outer edge, and a second cavity chamber for forming a shell, with the second cavity chamber having a center and being adjacent to the first cavity chamber. The injection molding apparatus and method also includes a first nozzle for a seal liner material positioned near the outer edge of, and in communication with, the first cavity chamber, and a second nozzle for a shell material positioned near the center of, and in communication with, the second cavity chamber. The injection molding apparatus and method further includes a mold core capable of being positioned in and moved between the first and second cavity chambers.