The molten metal injector system includes a holder furnace, a casting mold supported above the holder furnace, and a molten metal injector supported from a bottom side of the mold. The holder furnace contains a supply of molten metal. The casting mold defines a mold cavity for receiving molten metal from the holder furnace. The injector projects downward into the holder furnace and is in fluid communication with the mold cavity. The injector includes a cylinder defining a piston cavity housing a reciprocating piston. The piston pumps molten metal upward from the holder furnace to the mold cavity. The cylinder further includes a molten metal intake for receiving molten metal into the piston cavity. The intake may be a valve or an aperture defined in the sidewall of the cylinder.
 The subject matter of this application was made with United States government support under Contract No. 86X-SU545C awarded by the Department of Energy. The United States government has certain rights to this invention.