Toaru Kagaku no Railgun SS - Volume 2, Chapter 7

... ts were armed with ultra high frequency electromagnetic rifles and a large amount of detectors. Essentially, they had special electromagnetic firearms that could penetrate all forms of cover and would fatally destroy human cells and they had explosives that used those firearms.

The means of defense in a modern gunfight was not to see the bullet and evade it. Instead, it was to hide yourself behind something that functioned as a shield. As such, the ultra high frequency electromagnetic ri ...