Abstract: A rotary blowout preventer is provided having a resilient sealing body which is deformed about a drill string or sealing by means of a tapered actuator cone. The actuator cone is driven by a piston which is responsive to annulus pressure and which is also selectively responsive to opening and closing pressures such as for test cycling. A bearing box assembly is interposed between the piston and the actuator cone, thus enabling the actuator cone and resilient primary packing to rotate along with the drill string. The primary packing incorporates a replaceable, tubular central resilient secondary packing section which is supported in place by a releasable hanger assembly. The primary packing is rotatably driven by a bearing supported drive assembly incorporating drive dogs which establish driving relation with the sealing rubber thereof. The blowout preventer also incorporates an internal packing which may be controllably hydraulically energized in the event the packing should develop a leak during use.