In at least some implementations, a blow molding apparatus provides that portions of the parison are engaged by one or more clamping devices disposed on or adjacent to the blow mold parts, and that the blow mold is opened whereby the parison is torn apart between the clamping devices, into two or more pieces of the parison. In other implementations, the clamping devices may be moved relative to the blow mold to tear the parison, or the parison may be torn by a combined movement of the blow mold parts and clamping devices.