a technique directed to a process for injection molding fiber - reinforced thermoset plastic articles is disclosed . the technique includes forming a mixture of short lengths of reinforcing fibers with a thermosetting resin in a predetermined fiber - to - resin ratio and introducing the mixture to an injection molding cylinder . the volume of mixture introduced is at least a multiple of two of the volume of the mold chamber so that the injection plunger traverses the intersection between the molding cylinder and a stuffer cylinder a single time for a multiplicity of molding shots to minimize fiber breakage and balling . the injection plunger is adapted to precompact the mixture by being forced forward until a predetermined high pressure is sensed , indicating a hydraulically locked condition of the plunger wherein substantially all entrapped gases have been expressed from the mixture and there exists no substantial forward movement of the plunger . the position of the plunger in its precompacted position is noted and recorded so that further multiple injection shots may be made in predetermined volumetric amounts .