A private US munitions manufacturer. It operates a munitions plant in Iowa that has been the source of many of the artillery munitions used by the Israeli military during the Gaza genocide.
Day & Zimmermann, based in Pennsylvania, is a private munitions manufacturer. It operates the Iowa Army Ammunition Plant (IAAP), which has been the source of many of the artillery munitions used by the Israeli military, including 155mm rounds, fired by Israel's M109 howitzer guns, and 120mm M830A1 High Explosive Anti-Tank (HEAT) round, fired by Israel's Merkava battle tanks.
Mason & Hanger has operated the IAAP since 1951. Between 1998 and 2007, the factory was operated by American Ordnance, a joint venture of Mason & Hanger and General Dynamics. Day & Zimmermann acquired Mason & Hanger in 1999, and in 2007 it acquired General Dyanmics' stake in American Ordnance.
In November 2023, Israeli tanks fired M830A1 rounds while attacking a U.N. school in Gaza. The serial number on one of the rounds recovered from the scene of the attack suggests that it was manufactured at the IAAP by Mason & Hanger in December 1990.
On January 19, 2024, Israeli tanks fired M830A1 rounds in an attack that killed six-year-old Hind Rajab, her six family members, and the medics who attempted to rescue her, in the Gaza neighborhood of Tel al-Hawa. The serial number on an exploded round found inside the ambulance sent to rescue Rajab suggests that it was manufactured at the IAAP by Mason & Hanger in November 1996.
In December 2023, the U.S. government used emergency measures to approve the transfer of 14,000 M830A1 tank rounds to Israel without Congressional review. The transfer—from the existing inventory of the U.S. Army–was worth $106.5 million and funded by U.S. taxpayers' money.
Day & Zimmermann's factory in Texarkana, Texas, is the current supplier of M830A1 rounds for the U.S. Army. Between 2017 and 2021, the U.S. Army's supplier of these munitions was a Northrop Grumman factory in Plymouth, Minn.