@ShinGetsu
Yeah, no need for tank rounds. There are so many ways the military would easily win against that in real life, even without the Gustav Recoilless Rifle or tank canons.
50 Cal and various 10 to 20mm Auto Cannon rounds will kill those orcs easy. It's what Scout cars and various light Vehicles and APCs use to kill each other and those vehicles are even more heavily armored than any orcs possibly can.
Even if a Metal Orc could survive that shet, the infantry don't need to play nice and use Fragmentation Grenades. What's stopping the Japense army from using Concussive High Explosive Grenades like the MK3A2? Or worse, what is essentially an upgrade, the Satchel Charge, which is intended to blow up buildings and disable tanks.
Or EVEN worse, why not have a tank or artillery fire a Fletchette or Ball stuffing round at the Orcs.