The Advanced Gun System (AGS) developed for the DDG-1000 Zumwalt class destroyer is a 155 mm gun in a stealth mount. The gun (and the ship, in a sense, since it was built around the gun) was developed in response to the retirement of the battleships and the resulting gap in naval gunfire support for troops ashore.
|LRLAP 155 mm Round|
The AGS is a fully automated system from ammunition strike down and handling to loading and operation of the gun, itself. While this reduces the crew requirements it also requires an inordinate amount of internal volume especially that devoted to ammunition storage and movement. The AGS Intra-Ship Rearmament System (AIRS), which is the automated system for moving pallets from the flight deck to the magazine, consumes huge internal volumes. Both the gun and ammunition handling are all-electric as opposed to previous hydraulic systems. Power requirements are reported to be 800 kW per mount which precludes fitting the system to other classes of ship.
In summary, what the Navy has is a dedicated land attack weapon with fair range compared to conventional naval guns. This may well prove to be a very effective naval gunfire support weapon but the value relative to the cost seems suspect and, when the non-surface firing capability is factored in, the system seems overly restricted. One can’t help but wonder if the already developed Mk71 8” gun wouldn’t have been a better starting point!