The original requirement was for a 40-ton tank armed with a 105mm gun, and DRDO had to start from scratch. Midway through this process, the Army changed its requirement to a 120mm gun armed heavier tank, capable of going toe-to-toe with the American Abrams tank, which Pakistan, was about to acquire from the United States in the 1980s. Those were the benchmarks that the Arjun had to meet and the Arjun of today is more than a match for the Abrams and equivalent Western tanks in terms of armour, firepower, mobility and protection. DRDO also successfully test-fired the advanced Israeli LAHAT anti-tank missile, which has a much longer range. Pakistan still does not have missile-firing tanks, by the way. Now, if the Arjun is not exactly what the armoured corps wanted, the blame goes equally to army officials who set the requirements along with DRDO. Can one place an order with Tata for a Sumo type vehicle, keep changing the specs and expect a vehicle with the Indica's size and cost? While the Arjun's media trial continues, the project itself resulted in a number of successful spin-offs. For instance, the bulk of India's tank fleet comprises aging T-72 tanks, some 1,700 of which are in India's inventory. One successful upgrade effort includes the mating of the Arjun's turret with the T-72's chassis, christened the 'Karna.' This includes the Arjun's IGMS, a state-of-the-art, homegrown fire control system, Laser Warning System, Nuclear/Biological/Chemical detection and filtration system, Land Navigation System and night vision gear. Under trials now, the Army has indicated that it could order 300 or more Karnas in the coming years. DRDO's 125mm piercing-piercing tank round is also a direct spin-off from the Arjun MBT program. These rounds are meant for the T-72 tanks. Over 130,000 such rounds have been produced by the state-owned Ordnance Factory Board's (OFB) since 2001, saving the army over Rs 200 crores per year in foreign exchange. Another Arjun spin-off is the 'Bhim' self-propelled gun, which mates an Arjun chassis with the lethal Denel T-6 turret from South Africa, making it a system that is unmatched in the region in terms of firepower, mobility and survivability. A Rs 2,000 crore deal for 100 such guns is reported to be signed soon. Most dispassionate observers would agree that the above results are enough not to deem a Rs 300 crore R&D effort to build a tank from scratch a failure. And there are more Arjun spin-offs to come! http://www.rediff.com/news/2005/jan/17spec1.htm i did not know full info, could any one show some light on it and more information about it. i am posting all the sources i got.