WHAT DOES RED ARMY STANDARD 7.62×39 MEAN?

Fired flawlessly via my Glock. At 21ft went from 10 inch groupings all the way down to two in groupings making use of this stuff then back again to ten inch groupings just after I utilised it. Distinct as working day this stuff is exact with practically NO recoil. Wouldn't want this within a tactical scenario but in order to see how exact you truly