 In the late 1980s, it was thought that the protection level of the Future Soviet Tank (FST) could exceed 700 mm of rolled homogeneous armour equivalence at its maximum thickness, which was effectively immune against the contemporary M829 armour piercing fin stabilized discarding sabot.In the 1980s the most immediate method available to NATO to counter Soviet advances in armour technology was the adoption of a 140 mm main gun, but this required a redesigned turret that could incorporate the larger breech and ammunition, and it also required some sort of automatic loader.Although the 140 mm gun was considered a real interim solution it was decided after the fall of the Soviet Union that the increase in muzzle energy it provided was not worth the increase in weight.