Yak-9T - incredible firepower (or maybe incredible tank's lack of armor?)

[Igo kyu]

Originally Posted by JtD

I hope that you are aware that by far the most WW2 AP rounds were explosive rounds.

No offence intended, however:

In the context of tanks, I am not aware of that. Air to air AP may have been different, there wasn't that much armour in 'planes, and doing damage once the armour was pierced would probably be worth it.

For a reason. For instance, rounds having pierced armour do not retain most of their energy, unless the armour wasn't worth mentioning in the first place.

That is not what happened. If a shot hit some armour, then things happened very fast, microseconds not milliseconds. When there is an impact, the parts can rebound without damage, or one can be damaged, or very unusually, both. The reason it's unlikely that both will be significantly damaged is that it's more or less a race to be the last to pass the limit of elastic deformation. The item that reaches the limit of elastic deformation first, is deformed plastically, and damaged. The item that is damaged gives way to the item that is undamaged, and the energy that was stored in the elastic deformation of the surviving item is restored in the rebounding of that item to its normal shape (which is why it's silly for tanks to have hitpoints that can be whittled away in some other sorts of games, shot either pierces the armour, or does almost no damage).

For comparison, the very good German 30mm tungsten core round carried only 75% the energy of the standard AP round, at the muzzle. Further away, even less. It had far better penetrating power, more than two times as much at 500m, but if both rounds got through, the standard round would wreck far more havoc.

That's not what I understood of tungsten core rounds. They were compressed in the barrel to get a much higher muzzle velocity, and since KE= 1/2 MVsquared, though the mass might be less the higher energy made penetration much more likely. Sabot rounds were similar, apparently less accurate than normal AP rounds, but much higher velocity, and thus KE, and therefore more likely to penetrate if they did hit.