True to its ancestry as a breakthrough tank, the T-10’s steel hide was truly formidable for its era. The thickness of the front of the hull’s reached 120mm on the upper glacis and 100mm on the lower glacis. Because of the steep piked nose, the actual thickness of the upper glacis actually reached a jaw-dropping 320mm! According to military historians this protection level made it impervious to direct hits from 76mm and 90mm NATO guns at any conceivable distance, and based on calculations done with knowledge on the penetration performance of 120mm AP supplied by military historians like Ken Estes (who was himself an M103 crewperson), the T-10 would have been totally immune to both the Conqueror and M103, and still resistant to 120mm APDS at ranges of 2000 meters and above. One interesting thing to take note of is that the glacis armour on the T-10 was constructed of rolled homogeneous steel plates, whereas the Conqueror and M103 had an all-cast hull with a cast steel glacis of inferior hardness and strength.