US Navy Railgun

For the first time in history, the US Navy will publicly demonstrate their crazy railgun at the Naval Future Force Science and Technology Expo in Washington D.C. on February 4. The U.S. Navy plans to integrate a railgun that has a range of over 160 km (100 mi) onto a ship by 2016. By that time the Navy expects to have a weapon that can fire multiple projectiles per minute. The hyper-velocity rounds weigh 10 kg (23 lb) and cost about $25,000 each. Continue reading for a video and more information.

They have command guidance but are planned to be self-guided in the future.[44] The 18 in (460 mm) shells are fired at Mach 7. Currently the only US Navy ships that can produce enough electrical power to get desired performance are the Zumwalt-class destroyers; they can generate 78 megawatts of power, more than is necessary to power a railgun. Engineers are working to derive technologies developed for the DDG-1000 series ships into a battery system so other warships can operate a railgun.

[Gizmodo]