A Twitter account by the name of Tehran. azady/@Gloomily8 (Free Tehran) has posted two posts and accompanying photographs on their page depicting what appears to be an FN Herstal, former U.S. Government 5.56x45mm M16A4 Service Rifle. It is not known or confirmed if the image is actually from Tehran for that matter, but a cursory Google Image Search revealed this Twitter account appears to have been the first online poster of this particular photograph. It would also appear that these photographs are actually screenshots from a motion picture, due to the apparent movement of the light source.
Neither post makes much mention of the weapon and is more concentrated on what is going to be happening or will be planned to happen in the future in regards to the protests.
Notice the SKU imprint-
It would appear that this M16A4 is most likely diverted from U.S. Foreign Military Sales to Iraq. What could possibly confirm this is the design of the handguard. We know it is an M16A4 due to the M1913 Picatinny Rail a part of the upper receiver, of which an “A2” carrying handle is fastened to. What is being left out however, is the design of the handguard. If it is a Knight’s Armament “A4” handguard, it would be a very rare sight indeed. But most likely it is an “A2” style with the circular handguards and vertical vent ports. The “Hybrid” M16A4/A2 rifles were previously sold to the Iraqi Army-
And were subsequently seen/captured by the so-called Islamic State-
It should be noted that M16A4s are in service in Afghanistan with the Ministry of the Interior, in addition to M4/M4A1s are in service with numerous Afghan forces as well. But the amount in service in Afghanistan doesn’t seem to be proportional to the amount of M16A4s with the Iraqi Army, or circulating on the Iraqi black market.