Direct proof of use
Official U.S. Army and Rock Island Arsenal material directly documents an M115 203 mm howitzer in Iraqi service during the 1990 Gulf War. The Army's Rock Island Arsenal self-guided tour article says the Memorial Field M115 was captured by Iraqi troops during the Iran-Iraq War, later used by the Iraqi Army against coalition forces during Operation Desert Storm, and then captured by U.S. forces and returned to Rock Island Arsenal in 1991.
The Army Sustainment Command's Rock Island Arsenal ordnance page gives the same chain of custody: overhaul at Rock Island Arsenal in 1977, shipment to Iran, capture by Iraqi troops during the Iran-Iraq War, Iraqi use against coalition forces during Desert Storm in 1991, and U.S. capture before shipment back to Rock Island Arsenal for overhaul and restoration.
Sources: Army.mil RIA M115 Tour, ASC Rock Island Ordnance Tour
Timeline
The documented Gulf War example began as a Rock Island Arsenal-overhauled weapon sold to Iran in 1977. Iraqi forces captured it during the Iran-Iraq War, bringing the U.S.-origin heavy howitzer into Iraqi inventory before the 1990-1991 war.
In 1991, during Operation Desert Storm, the Iraqi Army used the M115 against coalition forces. U.S. forces subsequently captured the howitzer and returned it to Rock Island Arsenal, where it became a Memorial Field display piece.
Sources: Army.mil RIA M115 Tour, ASC Rock Island Ordnance Tour
Battlefield role
In the Gulf War record, the M115 appears as Iraqi heavy towed artillery rather than as a coalition weapon. The cited Army sources do not identify the Iraqi unit, firing location, target list, ammunition expenditure, or battle-damage result, but they do identify the operator, the 1991 Desert Storm context, and use against coalition forces.
The weapon's general role was heavy artillery fire support. Rock Island Arsenal describes the M115 as a 203 mm heavy howitzer, originally the M1 8 inch howitzer, with a crew of fourteen and a range up to 10 miles. Those background details explain why an Iraqi-held M115 would fit the heavy field-artillery category, while the conflict-use claim rests on the Army statements that the Iraqi Army used the howitzer during Desert Storm.
Sources: Army.mil RIA M115 Tour, ASC Rock Island Ordnance Tour, ASC M115 Fact Sheet
