Direct proof of use
The clearest public record for 5.56x45mm NATO-family ammunition in the 2014 War Against the Islamic State is Conflict Armament Research's October 2014 field dispatch on small-calibre ammunition recovered from Islamic State forces in Iraq and Syria. CAR documented 5.56 x 45 mm ammunition captured in northern Iraq during an assault on Islamic State forces in the Sinjar Mountains, where YPG forces recovered ammunition loaded into magazines of 11 M16A4 assault rifles.
CAR also documented expended 5.56 x 45 mm ammunition at former Islamic State firing positions between Gwer and Hawerah in northern Iraq. Peshmerga forces directed CAR investigators to positions that Islamic State forces had occupied before a Peshmerga offensive on August 10, 2014, and CAR recorded heavy concentrations of spent 5.56 x 45 mm, 7.62 x 39 mm, and 7.62 x 54R mm ammunition there.
Sources: Islamic State Ammunition in Iraq and Syria
August 2014 field evidence
The documented Iraq evidence falls into two dated episodes. In the Sinjar Mountains north of Bara, YPG forces captured 5.56 x 45 mm ammunition on August 4, 2014, and CAR documented it on August 11. The cartridges included U.S. Lake City production from 2005, 2006, and 2007, and Serbian Prvi Partizan production from 2007.
Between Gwer and Hawerah, CAR treated the ammunition as fired on August 10, 2014, and documented it on August 13. That sample included U.S. 5.56 x 45 mm ammunition made at Lake City from 2005 through 2008, Serbian 5.56 x 45 mm ammunition from 2009 and 2010, and Bulgarian 5.56 x 45 mm ammunition made by Arsenal JSCo in 2008.
Sources: Islamic State Ammunition in Iraq and Syria
Role in the conflict
In this conflict-use record, the cartridge's documented role is small-arms ammunition in Islamic State hands, including ammunition captured loaded in M16A4 magazines and ammunition expended at firing positions. CAR described 5.56 x 45 mm as a NATO-standard calibre in widespread use among Iraqi defence and security forces and noted that U.S.-manufactured 5.56 x 45 mm cartridges were used in U.S.-supplied M16 and M4 assault rifles of those forces.
The available direct source supports captured, recovered, and expended ammunition evidence in northern Iraq during August 2014. It does not establish a complete inventory of Islamic State 5.56 x 45 mm stocks, identify every rifle used to fire the recovered cartridges, or prove the chain of custody for each lot beyond CAR's documented field samples.
Sources: Islamic State Ammunition in Iraq and Syria