Based on the events in Europe, in 1940 a Tank Destroyer Board and a Tank Destroyer Commander were founded. Based on observations of the European battles it was thought the way to deal with fast moving tank columns was to deploy mass quantities of tank destroyers.
U.S. Army intelligence reports in April 1942 led to a specification for a more powerful tank destroyer. The need was urgent so the design and development was rushed and the design was accepted in September 1942 and put into production.
The M10 was not intended for use in close combat and as a result had thin armor.
Since the turret was open topped, the crews were vulnerable to grenades, shell bursts, and small arms. To help with this, some tanks were fitted (typically at divisional level) with armored covers.
Chassis / Hull
The top of the hull was shortened and the armor was reduced to save weight.
The chassis was from the M4A3 Medium Tank with the upper hull and turret were unique to the M10. The hull had bosses on it that could have additional armor attached.
A wading trunk could be fitted to protect the engine, and other waterproofing of the M10 could make it usable during amphibious assaults.
The 76.2 mm M7 anti-aircraft gun was installed. M7 gun could penetrate 100 mm at 1,000 yards. Velocity 2,600 ft/sec, range 16,100 yards. The AP round weighed 15 lb. The .50 cal fired at a muzzle velocity of 2,900'/sec.
Later, during production, due to the 76 mm gun, counterweights had to be mounted on the rear of the turret.
Tank Destroyer Armament Performance