Ordnance Factory Board (OFB) has received the bulk production clearance (BPC) from the Indian Army and the Ministry of Defence on February 18, 2018 for production of 114 nos of 'Dhanush', the first ever indigenous 155mm x 45 calibre artillery gun. The weapon is the first long rang artillery gun to be produced in India and it is a major success story of the 'Make in India' initiative.The gun is equipped with inertial navigation-based sighting system, auto-laying facility, on-board ballistic computation and an advanced day and night direct firing system. The self-propulsion unit allows the gun to negotiate and deploy itself in mountainous terrains with ease.'Dhanush' has been mechanically upgraded to fire standard NATO 155 mm ammunition and can accommodate both boll bags and the bi-modular charge system (BMCS) which have resulted in increasing the range . 'Dhanush' has also been electronically upgraded to enhance the firing accuracies, laying speeds of the existing gun and to provide compatibility with various kinds of ammo as well.The performance of 'Dhanush' has been evaluated under arduous conditions in several phases. The guns travelled extensively in towed and self-propelled mode in all terrains viz desert and high altitude with each gun clocking over 1600 km. Such an extensive exercise was carried out by the user for the first time for any gun system under the process of induction.The manufacture of a 155 mm modern artillery gun was initially a challenge for OFB. This was due to change in the vision parameters from 155x39 calibre to 155x45 calibre. OFB received the Transfer of Technology (ToT) documents pertaining to 155x39 calibre and then converted it to 155x45 calibre successfully.Dhanush' is the product of joint efforts by the OFB and the Indian Army with contributions from DRDO, DGQA, DPSUs such as BEL, PSUs such as SAIL and several private enterprises.