India was originally reliant on Russian FSAPDS for the T-72 which we procured along with the tank.
The lack of local ammunition for the tank fleet was regarded as a critical limitation so the DRDO was the initiator of FSAPDS capability at OFB, by setting up the HAPP (Heavy Alloys Penetrator Project) at OFB Trichy, which made even the crucial KE tungsten dart. The first FSAPDS were made for the 105mm Armed Vickers MBT (license made in India as the Vijayanta), followed by the 125mm for the T-72 and 120 mm projects for the Arjun.
Hence, the DRDO developed the 125mm Softcore ammunition (MK1) which was manufactured by OFB. While the overall design was DRDOs, the OFB was responsible for the sourcing of stuff like the propellant, and the production.
The OFB contracted for propellant from a Russian manufacturer in bulk & it was this which leaked. This because a) the rounds in question did not have adequate packaging to prevent leakage - heavy packaging in turns means the rounds get bulky and would not fit into the T-72 breech b) The propellant was not designed for the temperatures we face in India c) The Army, lacking any temperature conditioned facilities for its rounds, has many of its rounds are stored outside in either open lots (with tents) or in facilities, where as is typical in North India, the mercury really shoots up.
Coming back to the event, the leakage of propellant meant that a portion of the rounds were deemed unserviceable, segregated - with one portion to be re manufactured, the rest destroyed.
Meanwhile, the Army had also ordered several thousand rounds of Israeli 125mm FSAPDS rounds as a Kargil top up for the T-72.
On evaluating these against the earlier local MK1 rounds, the Israeli rounds had better performance as they had been developed later. The Israelis promised TOT as well. So the Army suggested that these be license manufactured with TOT. The Army though this was an easy solution to the quality issue with the OFB rounds and now all would be well. They suggested this to the MOD, and that was that.
So the MOD stopped the production of the DRDO penetrators at HAPP, had OFB production of the entire MK1 round shifted to the ostensible production of the Israeli 125mm rounds & these were to be be the future mainstay of the Army. In reality, this has not been ideal. There have been production issues with even these rounds, and the rate has not been slow and not upto meeting IA requirements for topping up its reserves.
The penetrator blanks are supplied by IMI, machined by OFB, and then assembled into rounds. The Israeli designation for this round is the CL3254M. Indian Army publicly refers to it as AMK-340A.
So the Army had stocks slowly built up of these rounds but which were also used up in live fire exercises and the like. We are now informed that the MOD considers this IMI deal and several others negotiated during the period, to have been tainted with corruption.
Meanwhile, citing the acquisition of the T-80 UD by Pakistan, the Army then purchased the T-90S. This induction too was conducted in a hamfisted manner, with several crucial steps including QA of systems such as the Thermal sight etc missing. We are paying for those today.
The T-90 tanks came with the BM-42 round (projectile assembly BM-17). The Army calls this round the AMK-339. The Russians arm twisted the Army and refused to provide the source codes for the ballistic computer on the T-90S, for India to use the AMK-340A/IMI rounds. As a result of which these tanks continue to use the BM-42.
Future T-90S built in India may be able to use Indian or Israeli rounds because the MOD asked DRDO/TATA to develop a 1:1 replacement for the original Russian Ballistic Computer, using the experience gained with developing the Arjun Ballistic Computer - both hardware and software. You'd have seen the pictures of it displayed at the recent Defexpo.
Basically, till this makes its appearance on local tanks and is retrofitted to Russian supplied kit/ tanks, we are limited to the BM-42. This round itself is just about sufficient for todays needs and is not cutting edge. Its functional, thats about it. This round can however be used for both T-72 and T-90s, and we are to order 66,000 of them after ordering some 10,000 earlier.
The blacklisting of IMI means that our supply of AMK-340A has now stopped and we are now clearly dependent on Russia for these older AMK-339s.
The Army solution to the possible issues with AMK-339 keeping pace with more heavily armoured Pakistani/Chinese tanks which may appear in the future, is to purchase huge stocks of INVAR UBK-20 missiles. Equipped with a tandem warhead, the hope is these will still allow us to defeat enemy armor.
Meanwhile, the one good news is that DRDO, despite having no firm GSQR to develop a MK2 version of their round, were stubborn and went ahead and sanctioned an own project to develop one anyhow. The Army demurred and was initially not interested.
Finally, sense seems to have prevailed, and they started taking an interest in the project after the first tranche of rounds were developed and the MOD approached them to have trials.
The first 30 odd rounds were put through AUCRT, improvements suggested, improved rounds developed, and 500 rounds were then cleared for further tests sometime last year. This MK2 round development, once finalized, now offers us the capability to restart our own 125mm FSAPDS line and move away from limited value license manufacture.
The performance of these rounds will be at the very least equal or better to the AMK-340As, which in turn were a bit better than those of the AMK-339 based on public, published information
The situation is pretty similar to how DRDO's BMCS has come as a possible solution for the Nalanda project. Bi Modular Charge Systems (think charges which can be loaded sequentially into a gun to get the range required) which were to be used with our upgraded 130 mm guns and the existing Bofors. The project went nowhere, facilities remained empty, and ultimately IMI got blacklisted. Now the local BMCS is in trials, if it passes, the entire complex will be fitted out on our own for series/volume production.
Anyhow, that is where the situation is today. FSAPDS manufacture for instance remains pretty tricky, even apart from design & development, and making our own penetrators end to end is important. Not just assembling rounds like several countries do, with the core penetrator being provided by others. The ARDE MK2 could be a possible solution, provided OFB/HAPP can handle the complexity.