The M3 Lee and M3 Grant were American medium tanks used during World War II. They were designed and produced to address the urgent need for armored vehicles in the early stages of the war. The M3 Lee was primarily used by the United States, while the M3 Grant was a variant used by British and Commonwealth forces. Here are key details about the M3 Lee/Grant:

1. Design and Development:

   • The M3 Lee/Grant was designed in the United States by the Rock Island Arsenal and other American manufacturers. It was intended to provide a quick solution to the need for medium tanks.
   • The design featured a unique configuration with a fully rotating turret mounting a 75 mm gun and a hull-mounted 37 mm gun.

2. Armament:

   • The main armament of the M3 Lee/Grant was a 75 mm M2/M3 gun mounted in the hull. This gun was capable of firing high-explosive and armor-piercing rounds.
   • In the turret, there was a 37 mm M5 gun for anti-tank and anti-personnel purposes.
   • The design of the tank was a compromise due to the limited availability of the 75 mm guns suitable for turrets at the time.

3. Crew Compartment:

   • The crew compartment was divided into two sections: the forward compartment housed the driver and the 37 mm gun operator, while the rear compartment housed the commander, gunner, and loader for the 75 mm gun.
   • Communication between the two compartments was limited, and the commander had to operate both the main and secondary guns.

4. Armor:

   • The armor of the M3 Lee/Grant was relatively thin compared to later tanks. It provided protection against small arms fire and shell splinters but was vulnerable to larger-caliber anti-tank weapons.

5. Engine and Mobility:

   • The tank was powered by a gasoline engine. The M3 Lee had a 340 hp Wright R975 radial engine, while the M3 Grant had a 410 hp General Motors 6046 diesel engine.
   • Its mobility was modest, and the design suffered from mechanical issues, especially in harsh conditions.

6. Service History:

   • The M3 Lee/Grant saw service in various theaters of World War II, including North Africa, the Pacific, and the Eastern Front.
   • It was used by both U.S. and British/Commonwealth forces.

7. Phasing Out:

   • The M3 Lee/Grant was gradually phased out as more advanced tank designs became available. The limitations of its design, particularly the hull-mounted main gun and crew compartment layout, contributed to its replacement by tanks like the M4 Sherman.

8. Legacy:

   • While the M3 Lee/Grant had limitations, it played a crucial role in the early years of World War II when the United States and its allies urgently needed armored vehicles.
   • The experience gained from the M3 Lee/Grant contributed to the development of more successful tank designs, including the M4 Sherman.

The M3 Lee/Grant, with its distinctive design, was an interim solution that helped meet the demand for medium tanks in the early years of World War II. Its unique features and compromises reflected the challenges faced by Allied forces during a period of rapid military expansion.