“20,000 U.S.-origin M-16 assault rifles”
They are/were Kuwaiti-owned military stock.
20,000 rifles is an unbelievably large number, this facility must be if not the sole, or single largest armory in the country.
“The regular forces are 15 500 people. The reserve - 23 700 people. Militarized formations (National Guard) - 5 000 people.” Source: http://topgun.rin.ru/cgi-bin/texts.pl?category=state&mode=show&unit=6050&lng=eng
In effect, every single rifle owned by the Reservist Command in the country was stolen, in a single robbery.
No doubt it was an inside job.