Ordnance ML 4.2-inch mortar

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	Weapon: Ordnance ML 4.2-inch mortar Type: Mortar Country of Origin: United Kingdom Year Adopted: 1942 Overall Length (mm): 1600.0 Overall Length (in): 62.99 Weight (kg): 510.00 Weight (pounds): 1124.36

The Ordnance ML 4.2-inch mortar was a British heavy mortar developed during World War II to provide a more powerful alternative to the standard 3-inch mortar. Initially adapted from a chemical warfare design intended for smoke and gas rounds, the 4.2-inch mortar was redesigned for high-explosive use due to battlefield needs. It had a caliber of 4.2 inches (107 mm) and was a muzzle-loaded, smoothbore weapon, operated by a crew of four to six men. The mortar could fire a variety of munitions, including HE, smoke, and illumination rounds, with a maximum range of approximately 4,100 yards (3,750 meters).

The weapon was first fielded by specialized mortar battalions and later issued to infantry divisions as demand for heavy indirect fire increased. It played a critical role during key operations in North Africa, Italy, and Northwest Europe, offering effective support in both offensive and defensive roles. The 4.2-inch mortar provided British and Commonwealth forces with a high-angle, high-volume fire capability ideal for urban combat, mountainous terrain, and softening enemy positions before infantry assaults.

Approximately 3,000 to 5,000 ML 4.2-inch mortars were produced during and after the war. It remained in service into the postwar years and was eventually phased out in favor of more modern designs such as the L16 81mm mortar. Its wartime service, however, left a significant legacy, earning it a reputation for powerful fire support and reliability in the most demanding combat environments. The weapon saw use not only by British forces but also by other allied nations, including the United States, which developed a derivative, the M30 4.2-inch mortar.

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