M7 Priest The 105 mm Howitzer Motor Carriage M7 was an American self - propelled artillery vehicle produced during World War II . It was given the official service name 105 mm Self Propelled Gun , Priest by the British Army , due to the pulpit - like machine gun ring , and following on from the Bishop and the contemporary Deacon self - propelled guns . History . Witnessing the events of the war , U . S . Army observers realized that they would need a self - propelled artillery vehicle with sufficient firepower to support armored operations . Lessons learned with half - tracks ( such as the T19 HMC - 105mm Howitzer on M3 Half - track chassis ) also showed that this vehicle would have to be armored and fully tracked . It was decided to use the M3 Lee chassis as the basis for this new vehicle design , which was designated T32 . The pilot vehicles used the M3 chassis with an open - topped superstructure , mounting an M1A2 105 mm howitzer and , following trials , adding a machine gun , the T32 was accepted for service as the M7 in February 1942 and production began that April . Before production had begun , the British Tank Mission had requested 2 , 500 to be delivered by the end of 1942 and a further 3 , 000 by the end of 1943 , an order which was never fully completed . As the M4 Sherman tank replaced the M3 , it was decided to continue production using the M4 chassis ( the M4 chassis was a development of the M3 ) . The M7 was subsequently supplanted by the M37 HMC ( on the " Light Combat Team " chassis that also gave the M24 Chaffee light tank ) . While the first M7s were produced for the U . S . Army , some were diverted to support the British in North Africa . Ninety M7s were sent to the British Eighth Army in North Africa , who were also the first to use it in battle during the Second Battle of El Alamein as well as their own Bishop , a self - propelled gun based on the 87 . 6 mm calibre Ordnance QF 25 - pounder gun - howitzer . The British did find problems with the M7 though , as the primary armament was of U . S . , not British , standard . This meant that the M7s had to be supplied separately , causing logistical complications . It was a problem that was only truly resolved in 1943 on arrival of the 25 - pounder - armed Sexton developed by the Canadians on a M3 chassis . Until that time though , the British continued to use the M7 throughout the North African Campaign and the Italian Campaign . The three assault infantry divisions ( 3rd and 50th British , 3rd Canadian ) that landed on Sword , Juno and Gold beaches on D - Day during the Normandy Invasion had their artillery regiments equipped with the M7 ; these were replaced by the standard towed 25 - pounder guns of the infantry in early August . It was also used in Burma and played a significant part in the Battle of Meiktila and the advance on Rangoon in 1945 . After the Sexton appeared , most British M7s were converted into " Kangaroo " armored personnel carriers . In U . S . service , the M7 was a great success . During the Battle of the Bulge , each U . S . armored division had three battalions of M7s , giving them unparalleled mobile artillery support . A total of 3 , 490 M7s — 4 , 267 if including the M7B2 — were built and they proved to be reliable weapons , continuing to see service in the U . S . and allied armies well past World War II .