timed sequence of events which also includes vacuum cleaning of glass particulate debris and any other contaminants through the central tube structure of the plunger mechanism so that such debris is not embedded in the parison in the preferred embodiment of the apparatus of the invention the lateral ports or vents 70 which serve to permit evacuation of air from the cavity 12 become closed off by the parison as it moves into the lower end of the cavity 12 however air passages are provided at the base of the plunger 18 to allow suction applied in the tube 58 to effectively increase the downward air pressure and force the parison firmly into the neck ring 16 fig5 and 7 illustrate the direction of air flow as the vacuum is drawn and fig6 illustrates the application of pressurized air during the counter blow step it is also comtemplated that a central air passage or throat be provided through the plunger 18 as shown in fig7 further construction of the plunger body or its outer surface may be of a ceramic material to retard heat transfer between the plunger and the parison whereby container formation becomes more uniform the air flow controller device or controller 84 shown.