Tank EX Tank - Ex / MBT - EX is the code name to a new tank developed by the Indian Defence Research and Development Organisation ( DRDO ) in 2002 . It is rumored to be called " Karna " , after one of the antagonists of the Indian epic ' The Mahabharata ' . History . The Tank - Ex / MBT - EX is a new prototype tank developed for the Indian Army by the Defence Research and Development Organisation ( DRDO ) in 2002 . This tank has been developed by integrating a modified low silhouette chassis of in - service T - 72 tank and a re - engineered Arjun MBT turret . The Tank - EX is intended to provide a solution for upgrading the Indian Army ' s aging T - 72M1 fleet . Tank EX is more of a hybrid between the Arjun tank and the T - 72M1 , with armor and firepower characteristics used from both models . According to sources at the DRDO at least 2 prototypes have been built , and improvements are being made constantly . After the trials are over as many as 300 tanks may be ordered from the DRDO in the future and further T - 72 hulls may be imported from Russia instead of utilizing the existing ones . Indian Army ' s Director General of Mechanised Forces ( DGMF ) Gen . Dalip Bhardwaj said on 5 July 2008 that the army had rejected Tank - EX . This was part of an announcement that there would be no further orders for Arjun tanks , and the army would be inviting participants from various countries to discuss future tank developments . Specifications . The Tank Ex at 47 tons is heavier than the T - 72M1 ( 41 tons ) and much lighter than the Arjun MBT , which tips the scales at 58 . 5 tons . The Tank - Ex has a power plant ( like on the Combat Improved Ajeya ) giving a power to weight ratio of / ton for a weight of 47 tons . This represents an improvement over the T - 72M1 ' s / ton with a weight of 41 tons and a power plant . The Tank Ex utilizes the Arjun MBT ' s 120 mm rifled gun firing unitary APFSDS and HESH semi combustible cartridge case ammunition . A total of 32 rounds are carried as compared to 39 in the Arjun and 45 two piece ones in the T - 72 . The choice of caliber , weapon design and ammunition allegedly make it superior to the in - service 125 mm 2A46 guns on the T - 72M1 . A global positioning system is provided for accurate navigation . This is a feature common to both the Arjun MBT as well as the Combat Improved Ajeya . The Tank Ex utilizes the " Kanchan " composite armor especially over its frontal arc ( turret as well as glacis ) giving it protection against both Kinetic and HEAT rounds . The usage of the Arjun turret design indicates that the Tank - Ex may also have its " ready " ammunition stored in the bustle ( as in the Arjun ) , separated from the crew and provided with blow off panels . This would be a significant protective feature in line with western design practices . The Tank Ex retains the T - 72 ' s mobility , with a road speed of 60 km / h and a cross - country speed of 40 km / h . With a maximum gradient climb at 30 degrees it remains in line with all variants of the T - 72 like the T - 72BM . The Tank Ex is better at trench crossing : 2 . 6 meters as compared to the T - 72M1 ' s 2 . 28 meters . Vertical Obstacles 0 . 85 metres tall can be surmounted . Shallow fording is quoted as 1 . 2 metres . The Tank EX should also have the possibility to fire the Israeli LAHAT missile from its gun - barrel , like the Arjun .