The Advanced Gun System (AGS) is a naval artillery system developed and produced by BAE Systems Armaments & Services for the Zumwalt-class destroyer of the United States Navy. Designated the 155 mm/62 (6.1-inch) 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 were 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, so the AGS has no ammunition and cannot be used. The Navy planned to remove the AGS from the ships starting in 2023.

The M982 Excalibur is a 155 mm extended-range guided artillery shell developed in a collaborative effort between the U.S. Army Research Laboratory (ARL) and the United States Army Armament Research, Development and Engineering Center (ARDEC). The Excalibur was developed and/or manufactured by prime contractor Raytheon Missiles & Defense, BAE Systems AB and other subs and primes in multiple capacities such as Camber Corporation and Huntington Ingalls Industries. It is a GPS and inertial-guided munition capable of being used in close support situations within 75–150 meters (250–490 ft) of friendly troops or in situations where targets might be prohibitively close to civilians to attack with conventional unguided artillery fire. In 2015, the United States planned to procure 7,474 rounds with a FY 2015 total program cost of US$1.9341 billion at an average cost of US$258,777 per unit. By 2016, unit costs were reduced to US$68,000 per round. Versions that add laser-guidance capability and are designed to be fired from naval guns began testing in 2015. By October 2018, over 1,400 rounds had been fired in combat.