[Rupert]

Note that HT gives DU ammo as (2) these days.

Also, this is a claim of double the penetration of a modern Russian/Chinese 125mm APFSDSDU round for only slightly more than double the muzzle energy. OTOH, the 125mm claims are for 1000m, so I suppose that's possible (but that means the muzzle penetration of modern 120mm and 125mm guns isn't far behind the performance claimed for this monster). I'm not convinced it's worth the investment.

The autoloader, missiles, etc. are all in the reach of modern weapons, it's just a matter of putting together the features of the various modern tanks in a single vehicle.

Also - I'm not sure why it's worth using such a weapon system as artillery except as an improvisation - artillery systems fire many rounds, and thus barrel life is a major consideration. One thing this gun will not have is a great barrel life, which is acceptable in a tank gun, but not in an artillery piece.

Note that in the current war the Ukrainians are finding that many modern western artillery systems are poorly suited for the type of war they're fighting because they don't have a very high sustained rate of fire due to barrel heating. It appears that wars' appetite for shells is as great as ever.