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 applying these things then again to 10 inch groupings right after I utilised it. Distinct as day this stuff is accurate with pretty much NO recoil. Wouldn't want this within a tactical predicament but if you would like see how correct you ac