Abstract: An assembly and method are provided for inflating a parison within a mold and forming the neck portion of a plastic container in a blow molding apparatus. The assembly includes a blow pin assembly mounted to a blow rod. The blow pin assembly includes an exterior surface having an annular cutting edge. The blow rod is movable along a vertical axis. The blow pin assembly is constructed such that at the time the mold is opened, the bottom end thereof is substantially incapable of engaging the lip of the blown container even if it is released unevenly from the mold. This is preferably accomplished by providing a blow pin assembly having a bottom end that is either above the shear steels at the time the mold is opened to release the container or has a sufficiently small diameter that it will not engage the container lip.