When the United States of America entered World War II, the US Army massively fielded the M5 3in (75mm) gun and the French canon de 75 M1897, which had widely been used in the Great War. However, the M2 105mm howitzer would replace them both as a field artillery gun from late 1941 and would be used on every theater of operations. This howitzer had a maximum range of 7 miles and fired high explosive and white phosphorous shells. When the M2 was mounted in a tracked vehicle, it became the M7 Priest, which was introduced in May 1942; about 100 M7s would be used by the British 8th Army in the Battle of El Alamein in November 1942.
As heavy artillery pieces, the US Army used the M1 “Long Tom” and the M115, which were a 6.10-in (155mm) and a 8-in (203mm)-caliber towed howitzers respectively. They were employed throughout WWII and the Korean War, as well, to soflten up enemy-held ground before launching an offensive. Also fielded by the British forces, the M1 would first see combat action in North Africa in late 1942. It was also fielded in Italy and France to provide fire support to spearhead infantry units. The Long Tom was also mounted in a tracked vehicle to become the M40 self-propelled gun.
The M2 howitzer was the most widely used field gun of WWII