The U.S. Navy has plans to integrate a railgun with a range of over 16 km onto a ship in the next 5-years, and this weapon, while having a form factor more typical of a naval gun, will utilize hyper-velocity rounds weighing 23-pounds, are 18-inches, and fired at Mach 7. The ultimate goal is to develop self-guided projectiles, and the Navy is projecting each round to cost around $25,000 each. There are currently some high velocity projectiles developed by the Navy that have command guidance, but their accuracy is unknown, nor it can survive a full power shot. There are only two Zumwalt-class destroyers (DDG-1000 series) that can produce enough electrical power to get the desired performance, generating 78 megawatts of power. Read more for two additional videos and additional information.
Even though the 23-pound projectiles have no explosives, their Mach 7 velocity gives them 32 megajoules of energy. The Navy is looking into other uses for railguns, including air defense, as with the right targeting systems, projectiles could intercept aircraft, cruise missiles, and even ballistic missiles. The Navy is also developing directed-energy weapons for air defense use, but it will be years before they become effective.
These railguns would be part of a Navy fleet that envisions future offensive and defensive capabilities being provided in layers: lasers to provide close range defense, railguns to provide medium range attack and defense, and last, but not least, cruise missiles to provide long-range attack. Railguns will cover targets up to 100 miles away that previously required a missile. Eventually, the Navy will enhance railgun technology to enable it to fire at a range of 230 miles and impact with 64 megajoules of energy.