Why is the Scharnhorst unkillable?

So myself and several friends have tried our best many times in naval ab to kill the Scharnhorst, with USS Arizona, Nevada, Alaska, the Kronshtadt, Novorossisky, etc…

No matter how many times we hit the ammo it’s always yellow or orange after multiple hits.
Aimbotters / cheaters such as msj love to use said vehicle, and be unstoppable.

It makes naval unbearable…