Correction: The last time tail gunners in the B-52 were ever used in combat were in Desert Storm in 1991. The gunner position was deleted from all remaining B-52s on 1 October 1991.
Currently there are tail/ramp gunners on CH-46s, CH-47s, CH-53s, MV-22s and CV-22s.
Were the guns removed in 1991, or did another crewmember (probably the EWO) take over the duties of gunner?