Whether the US military and the Chinese military realize it or not, a nuclear bomb is a sophisticated weapon that relyes heavily on that the bomb mechanism is intact before detonation. It is not a simple explosive gunpowder warhead.
I doubt if detonating a long range ballistic nuclear missile warhead fast enough can be achieved since the warhead mechanism will become demolished and dysfunctional within the time window required with a mach 5 or 6 impact. That is up to and including 7100 km/h or 4500 miles per hour. That is more than 2000 meters per second. The missile warhead will become shredded radioactive metal scrap as soon as it hits the ground or before it reach 10 meters in 0,005 seconds.
Anyway, I find it improbable that you can harden the warhead for it to be intact within the detonation window. By the way, it may also be detonated with the aid of explosives, but I don’t know. It used to be.
I find it improbable that they will ever test my assumption, except for in the computer realm, since the US and Russia and I don’t know if whether China has also signed a treaty that bans above ground nuclear tests. That’s why the US tested a nuclear bomb buried below ground for this purpose.
They can only test the effect from the nuclear blast, not if the nuclear warhead can survive impact long enough for it to be able to detonate. But I guess there is a chance they can detonate the warhead while it is still in the air and hope to penetrate the surface simultaneously. I think it is a slim chance.
Actually the regular long range ballistic missile is flying at Mach 17, but only at high trajectories.
It isn’t probable that the Chinese have ever signed a nuclear treaty.