Abstract: By providing a separate, independent, elongated, open-ended hollow conduit and positioning the conduit in the central sprue of an investment casting shell or mold, a unique dual chamber, bottom feeding system is obtained. In order to assure that the molten metal is fed to the bottom of the central sprue at the desired position, portal zones are formed near the distal end of the conduit and the molten metal is fed into the proximal end of the conduit. In the preferred embodiment, holding and locking means are employed to maintain the conduit in the desired position during the pouring process. In addition, the present invention also preferably employs a unique annular trap zone formed in the base of the central sprue in cooperating relationship, with the elongated conduit for receiving and holding impurities contained within the molten metal.