To understand the tank destroyers and their roles if and when I discuss anything TD in the future, one must first understand what is the Tank Destroyers.
The tank destroyers were founded in 1940/41 after the German blitzkrieg of Europe. From September 1939 to June 1940, the Nazis were able to conquer all of Europe with the use of highly mobile armor. American military officials and FDR were shocked at the speed of the Blitz and knew tanks were a key component of any military power going forward. The American military had in 1940 only 2 full Tank Divisions with poor equipment compared to the hundreds of Panzer German Divisions. The Tank Destroyer battalion was seen as a stop gap to help increase the effectiveness of armor divisions as well as bring more to the increased conflict that was surely to come. Tank Destroyers were made to use bigger guns and mobility at the cost of armor.
The M3 gun motor carriage was adopted as the first tank destroyer. A half track with a 75mm ww1 cannon attached to the back was seen as the best America had to offer in regards to destroying German tanks. They saw limited action in the early days of America’s entry in the war on places such as Bataan and in North Africa in 1941/42.
Soon after, the first tank version of a tank destroyer as we know it was the M10. Built on the chassis of a Sherman tank, the M10 sported a 76MM gun and movable turret. The turret did not have a latch to close and was open topped. It also had manual rotation speed vs electrical or hydraulic power so it was not a great turret by any means. This tank was built in 1942 and saw action until the end in 1945. It was however obsolete by 1943 and given to segregated Black TD units while the newer equipment went to many white units.
The M 18 came into the scene in 1943/44 as the deficiencies in the M10 showed the need for a better gun and speed/turret. The new TD was the fastest tank in the war and comparable to an M1 Abrams today, but at the cost of armor. With only 1 inch or less of armor, this tanks crew was always in danger and casualty rates could be very high in the 5 man crews. The 76MM it sported was deficient by 1943/44 as the German 88MM was the most feared tank of the war and German Armor was so superior to any allied tank fielded in the war. This tank saw action until the end of the war and was the most successful and Numerous tank destroyer we had
Finally in late 1944 and early 1945 to combat the German 88, the new tank destroyer had a 90 MM gun and electrical turret. This tank is arguably the best designed of the war but arrived late in 1944 and saw action in the last year only in 1945; tank was used in Korea because of its gun though.
The US Army deemed the Tank Destroyer battalions useless and a waste of time in 1946, bringing the Tank Destroyer to an end.