This was the 762x39 banned from importation because the feds thought it was AP. The steel core is dead soft steel. Shows what they know. Occasionally sold for nutty prices to people that think it is AP. Pic is box and black colored cases. It is commonly known as the "flame thrower ammo". Does have quite the muzzle flash.
I remember when this stuff was going for $1.99 for a box of 20, or less than $100 for a case of 1000. That was back in the early 90's. It was the cheapest 7.62 to be had at the time.