A forging apparatus comprising: a die for receiving a billet; and an extrusion punch for striking the billet when the billet is in the die, wherein the die comprises an upper die and a lower die that together form two separate cavities (140, 145); and each cavity comprises a first cavity portion (141, 146) in which the billet is received and a second cavity portion (142, 147) into which the billet is deformed when it is struck by the extrusion punch, and characterised in that: the two cavities are identical; the extrusion punch comprises a body portion and a striking portion, each of which has a longitudinal axis, the striking portion being received by a first cavity portion in order to strike the billet; the longitudinal axis of the striking portion is parallel to and offset from the longitudinal axis of the body portion; and the longitudinal axis (Y-Y) of the striking portion is offset relative to the longitudinal axis (X-X) of the body portion such that rotation of the extrusion punch about the longitudinal axis of the body portion by a predetermined angle results in the striking portion moving from a position in which it can be received by the first cavity portion of one cavity to a position in which it can be received by the first cavity portion of another cavity. a die for receiving a billet; and an extrusion punch for striking the billet when the billet is in the die, wherein the die comprises an upper die and a lower die that together form two separate cavities (140, 145); and each cavity comprises a first cavity portion (141, 146) in which the billet is received and a second cavity portion (142, 147) into which the billet is deformed when it is struck by the extrusion punch, and characterised in that: the two cavities are identical; the extrusion punch comprises a body portion and a striking portion, each of which has a longitudinal axis, the striking portion being received by a first cavity portion in order to strike the billet; the longitudinal axis of the striking portion is parallel to and offset from the longitudinal axis of the body portion; and the longitudinal axis (Y-Y) of the striking portion is offset relative to the longitudinal axis (X-X) of the body portion such that rotation of the extrusion punch about the longitudinal axis of the body portion by a predetermined angle results in the striking portion moving from a position in which it can be received by the first cavity portion of one cavity to a position in which it can be received by the first cavity portion of another cavity. the two cavities are identical; the extrusion punch comprises a body portion and a striking portion, each of which has a longitudinal axis, the striking portion being received by a first cavity portion in order to strike the billet; the longitudinal axis of the striking portion is parallel to and offset from the longitudinal axis of the body portion; and the longitudinal axis (Y-Y) of the striking portion is offset relative to the longitudinal axis (X-X) of the body portion such that rotation of the extrusion punch about the longitudinal axis of the body portion by a predetermined angle results in the striking portion moving from a position in which it can be received by the first cavity portion of one cavity to a position in which it can be received by the first cavity portion of another cavity.