The stuff we got is Russian. And it's not Mild anything. It's AP ammo. It's meant to punch light armor, and it does it just fine. You hit metal straight on - it goes straight through.
Now imagine that stuff, in belted form, being used against light armored vehicles. Ouch.
I remember, back in 2000 at IOAC, planning (map drill) anti-armor ambushes against BTR and BRDM equipped 'bad guys' using M240s with belted AP. Guys who had seen the inside of some dead ones in Bosnia affirmed that 7.62 AP will punch nice holes in them.
Needless to say, .50 cal just wrecks them. And the 25mm AP-sabot is complete overkill, actually less effective than .50.