There is some confusion in terminology here. The brass case is indeed discarded when the round is fired. Byt 'casing' he means the exterior of the warhead. The word 'round' is used for both the warhead+gunpowder+brass and then for the warhead itself. Larger artillery pieces do not use a brass shell case at all. The round is loaded, and then the powder is rammed in after it.
That is called the 'jacket' in all the years I have handled weapons that is the only correct term for it. The casing is where the powder goes. We were not talking about artillery pieces in relation to the comment by me on this issue. I know little about artillery, I do know about tanks and aircraft because they are a life long interest for me.
I can find no reference any U-core round being HE or otherwise carrying a charge. In all cases that I am aware of and can find reference to it is simply a KE attack on the target where the by products of the impact bounce around inside the target grinding up whatever is in there.
I believe that this is true, except that the 'products of the impact' are drops of metal and what they do is worse than grinding something up. -- Jim Dixon
The pieces in most cases are simply slivers of metal that breaks off the inside of the tank because of hyper-sonic shockwaves. They are not molten and do not in general cause a fire. Other than a lucky hit on a live round with the ammo door open there is little chance of starting a fire.