What kind of system using modern technology would be able to counter a railgun projectile on a vehicle (both land and sea)? Would a think slab of angled armour in the shape of "<" work to cover the entire thing that needs to be protected or would an all-or-nothing design work better? On the other hand, would making something with no armour and a very thin structural shell project better as it allows the railgun projectile to overpenetrate?

The railgun in question would be [this](https://en.wikipedia.org/wiki/Railgun#U.S._Navy_tests) railgun tested by the US Navy. The projectile would just be the solid sabot fired by that gun.