You're fundamentally mis-understanding how these would work. Kinetic bombardment weapons wouldn't be "fired". Their velocity is achieved on the front end when they're launched into orbit. To use them it's a relatively straightforward task to calculate their current position and velocity, apply a modest amount of force to push them out of a stable orbit, and then sit tight until they de-orbit at 22,000 mph on a very predictable path. The energy for that kinetic impact will be E = (1/2)mv^2. You'll lose some velocity to atmospheric drag, and maybe a small amount of mass will be burned off (though tungsten is quite heat resistant), but almost all of that kinetic energy will be delivered to the target. People forget that the whole purpose of retro burns in manned craft is that humans in flying bricks who hit the atmosphere at 22,000 mph tend to burst into flames and have to be picked up with a stick and a spoon. Tungsten doesn't melt for another ~1500° celsius. Tungsten rods hitting their target at 22,000 mph is a *feature* because it allows them to hit it sooner and makes them guaranteed kill weapons on any static target. This is particularly the case for bunkers since physics is efficient in dissipating kinetic impacts. Given a "choice" between moving all the not-very-compressible dirt around the impact site and the air in a bunker/cave/etc...the bunker will pancake like Rosie O'Donnell on a folding chair.