An injection-compression molding device for producing bottle preforms, comprising - a frame; - at least one molding cavity fixed to the frame; - at least one rod, connected to the frame so as to be capable of sliding with respect thereto; - at least one core, connected to the at least one rod so as to be capable of sliding therewith, adapted to be inserted into the at least one molding cavity defining a mold; - actuation means adapted to exert a mold closing force when the at least one core is inserted into the at least one molding cavity; wherein there is provided a joint connecting the at least one core to the at least one rod, characterized in that said joint comprises - a first part integrally connected and coaxial to said at least one core and defining a cavity; - a second part integrally connected and coaxial to said at least one rod and at least partially slidable in said cavity when the closing force is applied; - elastic means arranged in said cavity; said first part being provided with an inner side surface; said second part being provided with an outer side surface; wherein, in a first configuration of the joint, in absence of the closing force, the outer side surface is kept in contact with the inner side surface, by the bias of said elastic means, whereby the at least one rod and the at least one core are kept coaxial to each other; and wherein, in a second configuration of the joint, in presence of the closing force, a clearance is provided between the outer side surface and the inner side surface, said elastic means being pressed by said second part, whereby the at least one rod is adapted to rotate with respect to the core. - a frame; - at least one molding cavity fixed to the frame; - at least one rod, connected to the frame so as to be capable of sliding with respect thereto; - at least one core, connected to the at least one rod so as to be capable of sliding therewith, adapted to be inserted into the at least one molding cavity defining a mold; - actuation means adapted to exert a mold closing force when the at least one core is inserted into the at least one molding cavity; wherein there is provided a joint connecting the at least one core to the at least one rod, characterized in that said joint comprises - a first part integrally connected and coaxial to said at least one core and defining a cavity; - a second part integrally connected and coaxial to said at least one rod and at least partially slidable in said cavity when the closing force is applied; - elastic means arranged in said cavity; said first part being provided with an inner side surface; said second part being provided with an outer side surface; wherein, in a first configuration of the joint, in absence of the closing force, the outer side surface is kept in contact with the inner side surface, by the bias of said elastic means, whereby the at least one rod and the at least one core are kept coaxial to each other; and wherein, in a second configuration of the joint, in presence of the closing force, a clearance is provided between the outer side surface and the inner side surface, said elastic means being pressed by said second part, whereby the at least one rod is adapted to rotate with respect to the core.