Direct proof of use
The documented 12-gauge slug appearance in the 2003 Iraq War comes from a Multinational Security Transition Command-Iraq materiel delivery to Iraqi security forces in November 2004. DVIDS republished the American Forces Press Service story on the delivery, reporting that the rollout included 450,000 12-gauge shotgun rounds, with 200,000 of them identified as slug rounds.
The same DVIDS report stated that the equipment had either been issued to Iraqi army, Iraqi National Guard, or Iraqi police forces, or delivered around Iraq for distribution to personnel. The source therefore supports supply and fielding context for Iraqi security forces, but not a specific firefight, unit-level recipient, or individual slug expenditure.
Sources: Iraqi Forces Weapons Delivery
Delivery timeline
The reported slug-round delivery took place in the Iraqi force-development phase that followed the 2003 invasion. DVIDS dated the American Forces Press Service story to December 6, 2004 and described the relevant rollout as a November 2004 shipment by Multinational Security Transition Command-Iraq.
A CSIS study by Anthony H. Cordesman later summarized the same November 2004 Iraqi force-development equipment stream. It repeated the 450,000 12-gauge shotgun-round total and broader weapons package while noting that the precise force-by-force allocation of armaments was not made clear.
Sources: Iraqi Forces Weapons Delivery, CSIS Iraqi Force Development
Role in Iraqi force build-up
The slug rounds were part of a mixed small-arms, ammunition, armor, vehicle, communications, and police-equipment package intended to train, mentor, and equip Iraq's security forces. DVIDS attributed the delivery to Multinational Security Transition Command-Iraq and listed shotguns, pistols, AK-pattern rifles, machine guns, rocket-propelled grenade launchers, body armor, helmets, and vehicles in the same rollout.
Within that package, 12-gauge slugs are best treated as security-force ammunition supply rather than as a documented battlefield strike system. The available public sources show transfer and distribution to Iraqi government and security forces during the conflict; they do not identify the manufacturer, slug load type, recipient unit, or confirmed operational firing incident.
Sources: Iraqi Forces Weapons Delivery, CSIS Iraqi Force Development