 It retained the same 76.2 mm F-34 tank gun and, for ease of production, shared at least seventy percent of its parts interchangeably with the T-34.Testing at Kubinka showed that the heavier T-43 couldn't match the T-34's mobility, while its armour was still not heavy enough to stop the German 88mm gun.After the Battle of Kursk, Soviet planners realized that the T-34's biggest drawback was the ineffectiveness of its 76.2mm gun against the frontal armour of the new German Tiger and Panther tanks.