 XIX and later mountings limited to 40, 50 or 55 degrees elevation, however, the guns were controlled by an A.A. fire control system and the mountings were provided with A.A. shell fuze setters.The USN had developed a similar class of destroyer, the "Porter" class with eight Mk 12 5 inch/38 caliber (127 mm) guns in four Mark 22 Single Purpose (surface action only) twin mounts, limited to 35 degrees elevation, but with no provision for A.A. fire control and no on-mount fuze setters.The 40-degree elevation did limit the ability of the "Tribal" class guns to engage dive and high altitude bombers but they were still effective in engaging low altitude, level, and torpedo bombers and could still provide barrage fire over other ships being attacked by dive bombers.