Abstract: A rotary blowout preventer having a radially compressible packing to be sealingly engaged with and rotated by a drill pipe or kelly and a hydraulically actuated wedging piston for compressing the packing is provided with a rotatable bearing support which in an exemplary embodiment includes an inverted truncated cone interposed between the packing and the piston, which is rotatably mounted to the piston by a plurality of bearing races, along with a thrust bearing interposed between the packing and the housing enable the packing to rotate relative to the housing and prevents upward axial motion of the packing.