Abstract: A flexible die head for continuously extruding pipe may have a flexible ring mandrel (112). A second, open end (120) of the ring mandrel (112) near the die exit may be continuously and resiliently formed to a non-circular shape whilst extruding the pipe so as to provide an extrudate profile to counter slump in plastic pipe forming. Symmetric and asymmetric shapes may be formed by the ring mandrel (112). The second end (120) may be flexed or otherwise distorted by use of a flexing means (122). The ring mandrel (112) may also be necked in a circumferential portion to order to further improve the forming of non-circular shapes.