No he didnt, steel core is armour piercing ammo.
Not always.
Armor piercing ammo has a core of very hard steel or a heavy, hard metal like tungsten.
The core has a very sharply pointed tip.
Some steel core ammo is not armor piercing.
As example the surplus 7N6-PS 5.45x39 ammo.
The bullet jacket is very mild steel.
Inside is a mild steel core. The core is blunt on both ends and is not considered to be armor piercing, although it does penetrate thin steel better then a lead core.
Here's a sectioned 7N6-PS bullet.
Note the blunt-ended mild steel core.