Just wanted to chime in that in the linked video clip, at approx 1:15, you can hear what is clearly not English being spoken by the gentlemen firing the AK’s.
And the Iraqi Army is still using AK’s, RPK’s and other Soviet/Russian gear, as that is that their infrastructure is set up to use. While thousands upon thousands of weapons have been destroyed, there are still many many more out there that can be purchased.
Also, with the going rate for the M-16 or the M4 being about 3 times that of an AK, you can outfit your military with less money.