Direct proof of use
Conflict Armament Research documented a Polish kbk AKMS manufactured in 1982 among Kalashnikov-pattern assault rifles captured from Islamic State forces in Kobane, Syria. CAR's Kobane dispatch places the documented materiel in the battle of Kobane, which ran from September 2014 until Islamic State forces retreated from the city on January 26, 2015.
The evidence is a captured-weapon record rather than a named AKMS firing incident. CAR reported that its team worked with YPG forces in February 2015 to document weapons the YPG had captured from Islamic State forces; by then, much of the seized materiel had already been moved into YPG frontline stockpiles.
Sources: Islamic State Weapons in Kobane
Timeline
Islamic State forces began the siege of Kobane on September 13, 2014. During the battle, Kurdish forces seized significant quantities of weapons and ammunition from Islamic State forces, including Kalashnikov-pattern assault rifles later documented by CAR.
Between February 20 and February 27, 2015, CAR investigators worked with YPG units in Kobane to document captured Islamic State materiel. In the Kalashnikov-pattern rifle section of the dispatch, CAR identified one documented rifle as a Polish kbk AKMS manufactured in 1982.
Sources: Islamic State Weapons in Kobane
Narrative
The AKMS appears in this conflict as part of Islamic State's small-arms inventory around Kobane, not as a separately traced supply channel. CAR documented 280 Kalashnikov-pattern assault rifles captured from Islamic State forces at Kobane and described the group as drawing on mixed stocks from China, Russia, and Eastern European producers. The Polish kbk AKMS was one identified example inside that captured rifle pool.
CAR's report also describes how YPG forces handled captured Islamic State weapons. The YPG typically integrated seized weapons into its own stockpiles to supplement firepower, which means the same battlefield capture evidence records Islamic State possession and later YPG recovery. CAR did not identify the complete chain of custody for the AKMS or assign responsibility for its supply to Islamic State forces.
For catalog purposes, the AKMS role in the 2011 Syrian Civil War is therefore best described as captured insurgent small-arms materiel documented after the battle of Kobane. The source supports Islamic State possession and YPG capture of the rifle, while leaving quantity beyond the single documented Polish kbk AKMS and any specific firing incident unverified.
Sources: Islamic State Weapons in Kobane