| The original 140mm was borne out of rumors that the Soviets were going to field a tank with equal internal volume to a T-80 but weighing 60 tons, giving it a massive amount of armor.
Tests done with the 1st 140mm APFSDS produced found it could penetrate 1000mm of RHA easily, enough to get through the today's M1A2SEP turrent front(remember this was in the 80s). I bet with further development a 140mm gun could penetrate 1500-2000mm of RHA.
140mm ammo is 5 feet long and weighs something like 100 pounds |