New Russian heavy ICBM - Sarmatian

A 1 ton rod of metal is a 1 ton rod of metal. Hitting it with an ABM system might bend it or break it into separate parts but they will still do damage when they hit something.

It would be hard to stop, but not hard to deflect off target and a solid projectile needs real precision to be of any use at all because it needs to contact the target to be effective.

Nuke warheads are usually detonated above the ground and are not crater digging bunker busters. A one ton tungsten "sabot"
would destroy bunkers deep under ground. It would stay intact longer and penetrate deeper into the ground to deliver all that
kinetic energy at the target.

But what actual damage will it do?

It would be like getting hit by a full metal jacket bullet, it will punch a hole through but not much more.

Anything along the path of the penetration will be damaged but the whole building or underground structure will remain intact and operational.

I remember reading about some troops being transported in a truck with a shipping crate type rear trailer... they were in the shipping crate. The vehicle was attacked by a 23mm cannon but from their description it was not using HE rounds but AP-T rounds because they were sitting in the dark crate and these tracer shells would punch straight through the crate from one side to the other. They described it as being like fluorescent tube lights flashing on and off like when they start up... except obviously much more noisy. They were on the floor but the rounds were coming in from the top of the crate and out the other side near the top and everyone was OK except a bit deafened by the noise.

The point is that most underground bunkers are essentially tunnels with rooms all attached together so any given aim point you might get a room or you might get a tunnel or you might miss everything and just keep going down through the rock.

You could hit the bunker system with 100 penetrators all spread out and still not destroy one bunker by taking out all the rooms and tunnels.

I would say it would be more effective to use the most powerful nuke you have and hit the ground with several of those... one after the other... The earthquakes that would cause would be rather effective and the environmental damage of all that ground material vapourised is going to seriously compromise the local environment too.

If there is an actual plan for such usage, then it must be motivated by reality conforming expectations. Too much thread space is wasted
on essentially "stupid Russians don't know what they are doing" BS.

The problem with the Rods of God type concept is that it has to be very very accurate and actually make contact with the target... a target that cannot be able to move.

You might use it to destroy the Statue of Liberty or the Eiffel Tower or Big Ben, but even then these things will have a hole punched down them... they are not going to be blown to tiny pieces.

The whole idea sounds a bit stupid really.

When you look at the science of it it shows how silly talk of nuking incoming asteroids would be... even a direct hit by our most powerful nukes will do very little to a mountain sized chunk of rock and anything you blow off it is going to hit you too anyway... though it will now be radioactive.