I got a question for you GV guys....
why would they call this a "Tank Destroyer" not just this particular one, but all the "tank destroyers" are they not usually less armored, I know this one is.....I am just curious.
seems silly to call something a "Tank destroyer" when a Tank can easily kill. 
By design, a TD was to engage enemy tanks/AFV's and destroy them. The name of the game is mobility. By design, and infantry support vehicle was to engage enemy infantry and fixed fortifications. Because the roles were so different and the tools needed were so different most countries split the duties. As WWII went on, it was apparent that a tank could be and should be able to do both jobs satisfactory. I think the Panzer IV H, or perhaps an earlier version with the long barreled 7.5cm cannon was the first "MBT" in WWII. Once WWII was over and the Cold War began, the "Main Battle Tank" concept took right off and the TD role was elevated to the skies.
The other thing to keep in mind is that usually the TD design was meant for TD'ing first and foremost, and infantry support was a distant secondary thought. Case in point: the US 76mm M1A1 cannon found in the M4A3 and M18, the HE is rather weak in comparison vs the US 75mm cannon but the AP ability was quite superior. However, the 75mm was designed from the beginning as an infantry support cannon (origins prior to WWI, iirc), as was the Sherman M4 tank. It was the TD units job to destroy tanks, not the 75mm Shermans. The British would have 1 Firefly TD move in behind a rank of Cromwells and Shermans, once a German tank was spotted the Firefly was brought forward and they engaged the German tanks, not the Cromwells and Shermans. Ever notice the Firefly does not have a hull MG (not needing it is only part of the story, but still)?
