Dear JM, I repeat what I mentioned in my previous Post, above yours of 18th.
The cartridge shown is a .303 with the shoulder “badly formed” by one means or another.
NO relationship to the .315 Indian, which IS a 8x50R (Austrian Mannlicher) with a soft point round nose Projectile. The clear photographs on the Indian Board of Ordnance Factory website are quite clear as to the ID of the cartridge.
Now as to how the case shoulder was “deformed” to such an extent… an attempt to chamber it in an 8x50R Chamber ( very possible, given that the case in Question IS a Khirkee Arsenal made cartridge…) or even trying to chamber it in a normal .303 which has a separeted neck/shoulder remnant still in the chamber (Not an uncommon occurrence with Cordite Loaded ammo, having shoulder separations due to the Non-annealed nature of Cordite loaded cases and how they are formed.
One must remember that India has had the 8x50R as a sporting cartridge since just after 1907 (The(British) Military calibre Banning Laws) and of course during WW II, used a large quantity of 8x50R chambered Rifles, Carbines and MMGs derived from Italian sources in East Africa, so much so that Khirkee made the ammo for them, as well as using up Italian captured stocks.
To get the force necessary to “swage” a cartridge to have a neck and shoulder similar to an 8x50R would require the thrust of an MG (the Schwarzlose in this case), as a simple Straight-Pull Boilt action would not have the force to do it…
Jusr as an aside, my first attempt at making 8x50R cases ( i did reload Berdan original cases) was to sleeve a .303 case, having set the shoulder back using a .308 die first, and trim and fire form… quite good working cases (See Nonte’s Book on Cartridge Conversions.) This was back in 1967-8, the year Nonte’s book was first Published.
Anyway, the whole thing may remain a delicious mystery, but consider the evidence…and the co-incidences…Indian cartridge, use of 8x50R by India, shape and position of shoulder…need I go on?
regards, and lets’s keep digging…