Javelin attack is 4, and it is a thrown missile (unlike arrows). This alone, as said before, does the trick. The javelin need not even be AP (and it is not). It isn't a pilum. It's a thrown spear. I don't know how the math works. 4 attack...12 armour for African Forest Elephant. You do the math. And looks like the 4 attack is actually 6 against elephants (+2 vs ele). Also, luck plays a role (we can call it chance if you wish). Sometimes, none of your volleys kill.