This M3 A1 Anti-tank Gun is located in the room called "Les Alliés Seconde Guerre mondiale" (The Allies during the Second World War) in the back of the museum.  Combat Vehicle In the museum's display, the M3 A1 gun is attached to the back of a jeep. The M3 A1 was a portable weapon that U.S. troops, specifically the 1st Armored Division, employed in North African and Sicily. Development of anti-tank guns began before the outbreak of World War II and the U.S. Army opted for a 37mm canon because of its mobility. One limitation was the limited shielding which the gun provided, a fact which motivated soldiers to weld additional pieced onto the front of the gun.  Due to the gun's limited penetrating power (described below) and rapid advancements in German tank technology, the M3 A1 was replaced before the end of the war by heavier weapons (although it proved decently effective in the Pacific Theater). 

"18702 copies of this antitank gun M3 A1 were produced. It was in service in the U.S. motorized infantry. Its round of ammunition could only pierce a 25 mm armour from a distance of 915 m."