Although the United States Navy's rail gun is not that new anymore, its testing stages keep on proving that it will be a viable weapon in the future. Its latest test proves that might be sooner than later.
A rail gun is simply a device that shoots projectiles by using electromagnetic forces and not conventional gun powder or other explosive substances. This allows the gun to fire projectiles at much faster speeds which cause more damage, but also save space on deck for various standard weapon equipment and is much cheaper to fire a single shot.
The U.S. Navy named their first fired projectile "Velocitas Eradico" which roughly translates to "speed kills."
At the end of July 2017, the engineers hit another milestone. They fired two successive shots, something that was not done before. They fired 2 projectiles in 25 seconds at a lower energy level in order to see what it would do to the barrel and overall apparatus. At that rate, they concluded that 4 shots could be fired in under a minute, but now they have to test it at a higher energy.
Keep in mind, these projectiles travel at over 5,000 mph so the friction and compression are immense which is why this gun has to be tested again and again. If all goes well with the next round of experiments, the gun manufacturers say the weapon could be operational as early as 2019.