Sorry I am going to have to jump in here.... There is a difference between "Steel core" and the real deal which is "Hardened steel core AP ammo/Black Tip" is correct.... but the real reason the stuff you have was banned from import was simply the AK pistols; by having AK pistols emerge on the market the ATF used that as a basis to ban the importation of that ammo under the basis that it is "Armor piercing PISTOL AMMO".
Just like with the pistol braces.... The ATF plays the loop hole game too!
I once proved my opinion at a gun show, where a guy was wowing the tacticool crowd around his table by holding one of those bullets up with it stuck to a magnet while proclaiming.....
"See it's steel core armor piercing; THATS WHY its $1.00 each per 20 or $1.50 if you want to buy them loose."
He literally had a 50cal can sitting there with it full of rounds, so I bought one for $1.50 and proceeded to stick it to his own magnet.... then pull out my pocket knife and CUT THE BULLET IN HALF!
This video shows the same ammo