Rotary mould drum system configured for use in an installation for moulding food products from a pumpable foodstuff mass while rotating a mould drum around a longitudinal rotation axis by a driving unit, the mould drum system comprising: • a frame structure, • a support device connected to the frame structure, having an inner side, the support device being moveable relative to the frame structure between an open position and a closing position, • a shaft having a mounting side at which it is mounted to the frame and an opposite free end, where the shaft is configured to receive a hollow cylindrical mould drum having an inner geometrical cross section, the hollow mould drum having an outer mould drum surface comprising plurality of mould cavities having an opening in the mould drum surface, the plurality of mould cavities defining a geometrical shape of food products to be moulded, where an outer geometrical cross section of the shaft is essentially the same as the inner geometrical cross section of the hollow drum so as to allow the hollow cylindrical mould drum to be slideable attached to the shaft at the mounting side when the support device is in the open position, followed by moving the support device to the closing position such that the free end is supported by the inner side of the support device, and • a bearing construction, wherein the free end of the shaft comprises a first structure, • the inner side of the support device comprises a second complementary structure, where the geometry of the first structure is essentially the same as the geometry of the second complementary structure such that the first structure and the second complementary structure fit into each other when the support device is in the closing position, where the bearing construction is integrated into the support device so as to allow the second complementary structure to follow a rotational movement of the mould drum. • a frame structure, • a support device connected to the frame structure, having an inner side, the support device being moveable relative to the frame structure between an open position and a closing position, • a shaft having a mounting side at which it is mounted to the frame and an opposite free end, where the shaft is configured to receive a hollow cylindrical mould drum having an inner geometrical cross section, the hollow mould drum having an outer mould drum surface comprising plurality of mould cavities having an opening in the mould drum surface, the plurality of mould cavities defining a geometrical shape of food products to be moulded, where an outer geometrical cross section of the shaft is essentially the same as the inner geometrical cross section of the hollow drum so as to allow the hollow cylindrical mould drum to be slideable attached to the shaft at the mounting side when the support device is in the open position, followed by moving the support device to the closing position such that the free end is supported by the inner side of the support device, and • a bearing construction, wherein the free end of the shaft comprises a first structure, • the inner side of the support device comprises a second complementary structure, where the geometry of the first structure is essentially the same as the geometry of the second complementary structure such that the first structure and the second complementary structure fit into each other when the support device is in the closing position,