The tank had weaker armor than the M4 Sherman, at just 64 mm (2.52 in), compared to the Sherman's 75 mm (2.95 in). The M4, for instance, weighed up to to 38 tons.įurther trials with the M7 soon showed it to be somewhat ineffectual. The M7 barely scraped into the Medium Tank weight class, however, weighing a base tonnage of just 27. It was soon found this problem was caused by a number of parts being cast thicker than specified. It was soon apparent that this vehicle far surpassed the required weight limit even further than originally thought, as fully loaded, the tank came to weigh in at 28 to 29 tons.

The trial stages of the M7 were where the tank's biggest issues came to light. Too Heavy for a Light, too Light for a Medium The vehicle would be built by the International Harvester Company at the Bettendorf Works in Iowa. The commander, gunner and loader were placed in the turret, while the driver and co-driver/bow gunner were placed in the forward hull. Despite its small size, five men would crew this vehicle. M7s produced thereafter would be produced to the standard of the T7E5. After all these variants, it was the T7E5 that became the baseline of the M7 Medium tank. This was the main gun of the M3 Lee/Grant and M4 Sherman Medium tanks. T7E5: Almost identical to the T7E2, but rearmed with 75 mm (2.95 in) M3 gun. The only real change between the two was the use of the twin Hercules DRXBS diesel engines and Detroit gear automatic transmission in the E3, and the use of twin Cadillac engines and double hydramatic transmission in the E4. T7E3 & T7E4: Both of these variants had the same welded hull and turret. This was the standard issue gun on tanks such as the Churchill Mk.III Infantry/Heavy tank and Crusader Cruiser tank. T7E2: Cast upper hull, Wright R-975 engine, Warner Gear torque converter, armed with the British made 57 mm (2.24 in) Ordnance QF 6-pounder Mark III Gun. Its bespoke turret brought the ability to mount a larger caliber of armament and also slightly more room for the crew to operate. T7E1: Riveted hull, torque converter, formed homogenous plate turret. The turret of this model bore similarities to the M3 Lee/Grant's, with the same 37 mm (1.46 in) M5/M6 gun. T7: Welded hull, five-speed hydramatic transmission, volute spring suspension based on the M3/M5's. The first built prototype of the M7, the T7.

Medium modern tank