WHAT DOES RED ARMY STANDARD 7.62×39 MEAN?

Fired flawlessly by way of my Glock. At 21ft went from ten inch groupings down to 2 in groupings making use of this stuff then again to 10 inch groupings soon after I utilized it. Crystal clear as day this stuff is precise with pretty much NO recoil. Wouldn't want this in a very tactical condition but if you wish to see how exact you truly check ou