The Soviet T-43 medium tank was a prototype developed during the Second World War as a possible replacement for both the T-34 medium tank and KV-1 heavy tank. The project's aim was to build a medium tank with heavier armour, but it turned out that what was needed to counter German advances in tank technology was better armament, and the T-43 was cancelled in favour of a more heavily-armed T-34-85.
Somewhat historically inaccurate the in-game T-43 basically have the same armaments as the T-34-85 in the 100mm D10T. The main strength of the T-43 over German and American counterparts are turret and hull traverse speed which makes it a good option for close in fighting. Take heed, tier 7 puts the tank in games with top tier tanks and should be played accordingly.
100mm D10T (better damage/minute and rof then the 122mm option)
Unlike it's tier 6 sibling T-34-85 the tier 7 class puts it up against some stiff competition drivers should be wary about this as while better armoured the opposition in it's class is way more deadly.