The railgun has been the weapon of wonder and secrecy for a few decades now. Though only thought of as fiction, the US Navy adopted it for testing. In that testing, it was discovered that a while it's cool to fire a projectile at Mach 7, it's most likely never going to go operational, and now in the military complex version of limbo.

Why, you ask? That's above my pay-grade. But the Pentagon has requested far less money for this project this year than it has in past years. That doesn't mean that they've worked out all the kinks, that means the budget will eventually diminish to nothing going forward.

While it's cool to liquefy enemy armor at extreme distances, it's not "Tank driving through car" awesome, and won't command that kind of fiscal energy and resources.