The Advanced Gun System (AGS) is a naval artillery system developed and produced by BAE Systems Armaments Systems for the Zumwalt-class destroyer of the United States Navy. Designated the 155 mm/62 (6.1") Mark 51 Advanced Gun System (AGS), it was designed to provide long range naval gunfire support against shore-based targets. A total of six of the systems have been installed, two on each of the three Zumwalt-class ships. The Navy has no plans for additional Zumwalt-class ships, and no plans to deploy AGS on any other ship. AGS can only use ammunition designed specifically for the system. Only one ammunition type was designed, and the Navy halted its procurement in November 2016 due to cost ($800,000 to $1,000,000 per round), so the AGS has no ammunition and cannot be used.