APHE

From Battleground Europe Wiki

APHE (Armor Piercing High Explosive)

APHE is an AP round with a small explosive warhead that explodes inside of the target after penetration, so it has the ability of causing more severe damage than a plain AP round. This ability comes at the price of lesser penetration, due to lower mass and the weaker structure of a shell with explosive filler, but penetration still depends of kinetic energy.