- Why isn't this thing working?
- — A Marine firing the Railgun at a vehicle.
The Railgun, if charged, uses magnets to fire a blast of Gruntiness. In doing so, it can should be able to kill most anything, but because it was manufactured by puny earthlings, it is cannot destroy much
It can't even kill a Mongoose, but is it good at destroying Spartans, if you aim for the face. A common theory is that 343 Industries wanted to see how useless of a weapon they could develop, and then implement it into Halo 4.