It’s easy to forget that the original rationale for the DDG-1000 Zumwalt Class centered around naval gunfire support for troops ashore, as the ship’s estimated costs have risen and its missions have proliferated. Heavily armored US battleships with massive 16-inch (406 mm) guns once performed extremely well in this role, as their volkswagen-weight shells gave enemies pause. USS Iowa was brought back into service during the Reagan era, but she was decommissioned again in 1990. That left America with a floating museum in Los Angeles, and a gap in its options.
While European manufacturers are fielding guided, long range adaptations of existing 127mm/54 and 76mm shells, the Zumwalt Class will be getting an entirely new Advanced Gun System that fires the same 155mm shells used by field artillery ashore. The goal was to combine the wide range of available 155mm shell options with extra-long range, GPS precision guidance, and rapid fire.