The upcoming USS Lyndon B. Johnson (DDG 1002) may be the first surface combatant to mount a rail gun. Still undergoing construction at the Bath Iron Works, the USS Lyndon B. Johnson is the third and likely final ship in the oddly-shaped Zumwalt class of destroyers, which first put to sea a few years ago. Once slated to comprise some 32 ships, budget cuts have reduced that number dramatically even though the US Navy sorely needs the stealthy littoral combat ship to bolster its in-shore capabilities around the world.
The Johnson, however, may be the first warship to mount a rail gun, which recently concluded testing with satisfactory results. The Zumwalt class has been identified as more suited to use emerging technologies, like rail guns, due to its superior electricity generation capability over previous destroyers and cruisers at 80 megawatts; Lyndon B. Johnson specifically is being studied because it is the latest of the class, while the previous two ships would be less likely to initially field the capability due to the testing schedule. The rail gun would likely replace one of the two Advanced Gun Systems.