A molten metal supply system (90) includes a plurality of injectors (100) each having an injector housing (102) and a reciprocating piston (104). A molten metal supply source (132) is in fluid communication with the housing (102) of each of the injectors (100). The piston (104) is movable through a return stroke allowing molten metal (134) to be received into the housing (102) from the molten metal supply source (132), and a displacement stroke for displacing the molten metal (134) from the housing (102). A pressurized gas supply source (144) is in fluid communication with the housing (102) of each of the injectors (100) through respective gas control valves (146). The gas supply source (144) is used to pressurize a space formed between the molten metal (134) and the piston (104) during the return stroke of the piston (104) of each of the injectors (100).
