WHAT DOES RED ARMY STANDARD 7.62×39 MEAN?

Fired flawlessly as a result of my Glock. At 21ft went from 10 inch groupings right down to two in groupings employing these things then back again to 10 inch groupings following I applied it. Very clear as day these things is correct with nearly NO recoil. Would not want this in a very tactical scenario but if you want to see how exact you truly c