Afghanistan was a disaster of the first
magnitude for the Soviet Army which was no longer the Red Army
of WW2. I, too, have read info from the war and it is shocking
to learn the true depths to which the Russian army fell as time moved on.
Alcoholism, drug use, suicide, self-wounding, and desertion become more and more common to the troops in a state of near total demoralization.
As for the ammo use it is fascinating to read of troops who even when ordered to aggress went into it in a defensive mode by using maximum firepower. Sometimes the goal of the troops was to scare the enemy away rather than take a chance on casualties.
The army used a wide variety of supplies from stores dating perhaps back to the WW2 era so it is not surprising some of it was not adequate.