Industry sources told IHS Jane's that the guns would be handed over to Bharat Forge, Punj Lloyd and Tata from the private sector and the state-owned Ordnance Factory Board (OFB) sometime in October.
The four companies, which will be allowed to form overseas tie-ups for the upgrade, will have 12 months to complete the retrofit before offering the guns for trials. Thereafter, one gun will be shortlisted and its vendor awarded a tender to upgrade 300 M-46s.
The OFB and Israel's Soltam upgraded 180 M-46s to 155 mm/45 calibre under a USD45,524,137 contract awarded in 2001; they equip 10 artillery regiments.
The M-46 upgrade is a delayed response to the army's 1999 Field Artillery Rationalisation Plan, which aims by 2027 to acquire 2,800-3,000 155 mm/52-calibre towed, wheeled, tracked and mounted guns and 155 mm/39-calibre lightweight howitzers.
India's last major artillery acquisition was the 1987 purchase of 410 Bofors FH-77B 155 mm/39-calibre towed howitzers from Sweden. The army currently has around 200 guns in service following cannibalisation due to a shortage of spares.
The army is planning to buy 144 OFB-built 155/45 cal FH-77Bs, prototypes of which are in their final round of trials.