The first Arms Manufacturing facility on the site was a gunpowder factory, which was started in 1787 and began production in 1791, whilst a Gun & Carriage manufacturing facility was set up nearby in 1801.
In 1904, a Rifle Factory was established at Ishapore, and began production of the Lee-Enfield rifle, which has continued- more or less- until the mid-1980s, and possibly the present. The factory also manufactured the Vickers-Berthier (VB) light machine gun, which was adopted in 1932 by the Indian Army and still remains in reserve use.
Military rifles manufactured at Ishapore pre-1949 are stamped "GRI" on the buttsocket, referring to George Rex, Imperator (i.e. King George VI, last Emperor of India), whilst military rifles manufactured post-1948 are stamped "RFI", which stands for Rifle Factory, Ishapore.
The Ishapore Rifle Factory is controlled by the Ordnance Factories Organisation of India. The organisation and the Ordnance Factory Board are notoriously secretive regarding production figures for military rifles, making the exact number of rifles produced at the arsenal almost impossible to determine.