Those Lee's are certainly IOF = Indian Ordnance Factories .315 Sporting rifles made at their Ishapore factory, see:
http://ofbindia.gov.in/products/data/weapons/wsc/5.htm
They shoot the .315 IOF cartridge made at the Dum-Dum ammunition factory. The .315 IOF is nothing else than the old 8x50R Mannlicher, Austro-Hungarian service cartridge in WW1. The Indians still load it to the original ballisics. When the .303 military cartridge was outlawed by the Brits in 1904?, Bsa chambered their Lee-Speeds to the non-interchangeable 8x50R Mannlicher of all things for the Indian market.See:

http://ofbindia.gov.in/products/data/ammunition/sc/14.htm