What we have today is:
Tungsten Carbide guns
Depleted Uranium guns
But I suspect that they would use HEAT round equivalents, as that is what fighters from WWII used, and fighters have continued to use.
Actually in WWII they used combinations of normal bullets, Incindiary, and HEAT.
But all this is about it changing the weapon hit effect for TVWP... and possibly the impact explosion.