Science Navy railgun fires 40-lb. bullets at Mach 7

Navy railgun: A Navy prototype of an electromagnetic railgun marks a major step in the process of installing the weapons on Navy vessels.

John F. Williams/Navy Media Content Service/AP

The first weapon-scale prototype of a futuristic Navy railgun began undergoing firing tests last week, the next big step toward putting the electromagnetic superweapon on U.S. warships by 2020. The Navy envisions using railguns to destroy enemy ships, defend against enemy missiles, or bombard land targets in support of Marines hitting the beaches.