Unclear what payload Agni V can carry at the maximum 5,000 km range.
Agni 5's second test.
Notably the second Agni test was for one warhead but what about the three warhead MIRV testing?
Comments on Agni 5's first test - which took place in April 2012
India conducted its second Agni 5 ICBM test flight from Wheeler Island, Orissa on September 15, 2013. The Agni 5 has the range to fire a 500 kg warhead 8,000 km covering China, Japan, parts of Russia, most of Southeast Asia, much of Australia, Iran, Saudi Arabia and parts of Western Europe.
The Agni 5 is about 17 meters long, weighs 50 tonnes and has three rocket booster stages. It can be launched from a road mobile vehicle, hardened silo or from a special railway wagon.
The first test of the Agni 5 missile was conducted on April 19, 2012. The development of Agni 5 began in 2009 (according to DRDO). It may begin to be deployed from 2015.
The highly publicised second test is to a degree domestically aimed at justifying the high expense of missile development to the public and broader Indian Government (which has many competing interests for the money spent). The launch is a genuine source of pride for many in India and concern in Pakistan and China. Information on the Agni 5 ICBM (defined as 5,500+km range) test was highly detailed. Almost all parametres except multiple independently targeted re-entry vehicle (MIRV) separation may have been tested.
The Agni 5 is arguably an Agni 3 with a third stage. The Agni 5 range may be 5,000 km with a 1,500 kg payload (with 3 multiple re-entry vehicles (MIRVs)) and (reportedly) 8,000 km with a 500 kg (one RV) payload. Agni 5 is specifically designed to have an average (probably 1,000 kg payload) range to strike all of China.
One of several reasons for developing the Agni 5 is as a response to China's similar weight, highly land mobile DF-21. While the DF-21 has an estimated range of only 3,000 km, when placed near the China-India border a DF-21 could hit all targets in India. In contrast an Agni 5 on the Indian side of the same border needs to boost warheads the length of China (5,000 km) to hit Beijing and Shanghai.
India's planned SLBMs in indigenous SSBNs will eventually provide the most survivable second and first strike option. Notably the US, France and UK have steadily shifted the majority of their active nuclear warheads to SSBNs over the last 30 years.
India's SLBMs from the defendable waters of the Indian Ocean will need a range of at least 6,500 km to hit any target in China. India's proposed plan of fitting 3 - 5,000 km range navalised Agni 3 SLBMs to its future SSBNs would require these SSBNs to transit the dangerous chokepoints in the Indonesian Archipelago to get within range. Chinese SSNs may guard these chokepoints. These high SLBM strategic and technical requirements in part explain why India at present is emphasising the land mobile Agni 5 component of its evolving nuclear triad.
Shorter range Prithvi and Agni 1 and 2 missiles encompass Pakistan but Agni 3+ are needed to reach much of China and Agni 5 all of China. The proposed future Surya ICBM class will be able to hit any targets on the planet particularly other nuclear powers.
Agni 5 is or will be “all-composite” that is light casings in its booster stages to extend its range or to permit a heavier payload. According to DRDO sources, an MIRV payload would be significantly heavier since it would consist of several nuclear warheads, each weighing about 400 kg. A five-warhead MIRV, therefore, would weigh two tonnes.
About four additional and successful Agni 5 tests will be required before Agni 5 can be deployed (perhaps in 2015 more likely 2017) as India's long range deterrent missile.
See this blog's reports of Agni 5's first test at http://gentleseas.blogspot.com.au/2012/04/latest-news-of-agni-v-test-may-be.html .