M-3 37mm

In 1937, the United States Army after years of trying to build an anti-tank gun model that improved those in stock, acquired two 37mm Rheinmetall PaK-36 guns in Germany. After studying them in detail, three prototypes were designed, designated as T7, T8 and T10, with different types of block breeches. Finally, the hand operated vertical sliding block breech T10 model was chosen and standardized as 37mm Gun M3 in 1938. This gun was soon phased out due to the increase in tank’s armour with the outbreak of WWII and was relegated to infantry support missions, where it lent good services until the end of the war. The M3 anti-tank gun was used by other armies, resulting the Chinese National Revolutionary Army as the largest user, with almost 1,700 guns in service.  France, UK and the USSR also used the M3 but in small quantities. Different variants of this gun became the main weapon of vehicles such as the M-8 Greyhound armoured car, and the M-3 and M-5 Stuart light tanks.

M-3 37mm anti tank gun gallery and more info