Of 114 ordered, first lot of 6 guns handed over to Indian Army in 2019 but could not be used so far because of muzzle break hits

Three years after the Dhanush artillery gun was handed over to the Indian Army, the Indian-made follow-on of the Swedish Bofors 155 mm howitzer finally cleared the “confidence firing” tests at Pokhran on March 8. This paves the way for the formal induction of the first indigenous 155 mm artillery gun into the Army.

The coming good of Dhanush will provide relief and momentum to India’s artillery modernisation programme, which requires Made in India efforts to deliver quickly after the Government’s recent decision to stop import of weapon systems, including artillery guns.

Repeated incidents of muzzle break hits had prevented the operationalisation of this 155 mm 45 calibre weapon and delayed the artillery modernisation program. A muzzle break hit occurs when the shell damages the front end of the barrel when fired instead of passing through it cleanly.

For over a decade, the Indian Army has patiently hand-held the effort of the Gun Carriage Factory to develop the gun and “iron out” what it termed as “a few teething issues”.

“Reliability Firing (2 Second line firing) of Dhanush Gun completed today at Pokhran Field Firing Range successfully. 2 guns fired 90 rounds each (including 35 rounds with Zone 6) flawlessly. All decks cleared for formal induction,” acknowledged Additional Secretary Defence Production Sanjay Jaju.

The first lot of 6 Dhanush guns out of the 114 ordered by the Army were handed over to the Army in 2019. Subsequently, 11 more guns have been delivered. But the induction and operationalisation has been stalled by the recurring problem of muzzle hits.

Dhanush has been developed on the basis of transfer of technology (ToT) documents provided by Bofors along with the 1986 deal. But due to the controversy over alleged payment of bribes to secure the deal, the ToT element was not actioned.

About 2010, the erstwhile Ordnance Factory Board (OFB) decided to develop a follow-on version of the FH-77 Bofors gun using the know-how gleaned from the ToT documents and using its experience of up-gunning older artillery guns.

The Dhanush was developed for a longer strike range of 38 km as compared to 27 km of the old Bofors, which had a 155 mm 39 calibre barrel. The range extension required a longer barrel ((45 calibre) and a modified double baffle muzzle brake (MDBMB) system to limit the stress on the structure to 155/39 levels. A design flaw which was resulting in muzzle hits has now been corrected, and its reliability validated through the second round of reliability tests.

Ninety rounds were fired from each of the two guns fielded for the two-phase Reliability Trials at the Pokhran Field Firing Range in Rajasthan. Additional Secretary Jaju acknowledged that all requirements were validated in the trials.

The rate of fire is stated to be 3 rounds in 15 seconds for bursts, 15 rounds in 3 minutes for intense firing and 45 rounds in one hour for sustained firing. The weight of the Dhanush is 13 tons, which is 700 kg more than that of Bofors FH-77. The barrel is 877 mm longer. Over 5,500 rounds are reported to have been fired from this gun in various rounds of trials.

Besides longer range, the Gun Carriage Factory claims superiority of the Dhanush over the Bofors on many other counts. Among the new features is an auto laying system based on the Fire Control Computer System as compared to the manual system of the old Bofors Gun. The gun has an Advanced Gun Sighting System with a day camera (CCD), night camera, laser range finder (LRF) and NFOV and WFOV, officials explained. Bofors only has optical day and night sight.

Dhanush also has an on-board Advanced Tactical Computer for targeting. For the Bofors FH-77, ballistic calculations had to be done at the command post. It also has an Inertial Navigation System (INS) and GPS for guidance.