Grumpy, I must echo your's and Mark's thoughts on this matter.
The barrels of my military rifles are clogged with what seems to be centuries of crud and copper fouling. It doesn't seem to matter whether the bores are worn and pitted, like the Russian/Soviet ones, or bright, shiny, and sharp, like my Finnish M39: a cleaning session after an afternoon at the range will invariably produce clouds of black crud in the hot water wash and then, when the bore cleaner is applied, the green verdigris from copper jackets is also never-ending. Even sessions with the almighty JB Bore Paste still have not restored the bores.
I also agree that corrosive primers are a terrible thing, which is why I give a bath of boiling water and a bronze brush treatment to begin with, and then some Windex (window cleaner with some ammonia) to neutralize the corrosive primers of the military surplus ammo I shoot.
Another issue is improper cleaning: a steel cleaning rod may be indestructible, but shoved down the muzzle, it will ruin the most important part of the bore.
Even then, it is often possible for one to find a bullet and load that will shoot well out of even a hideous-looking bore.
But in India, our brothers will not have the luxury of choosing bullets and powders -- they must take whatever is available from the shelf, assuming there is ammunition there to begin with.
Also, there is no guarantee that a given bore will clean up and shoot well with any load. As the saying goes, the proof of the pudding is in the tasting, and the only way one can know for sure is to take the rifle to the range and give it a try, and then try appropriate cleaning methods, and then take another trip to the range with, perhaps, different ammo.
The question here involves a much more extreme example of a question our Brother Herb posted a short time ago: He showed pictures of two classic and voluptuous bolt action rifles, along with a picture of a lowly brand new Savage with a plastic stock -- a real ugly duckling compared to the first two.
Most of us told Herb to take the Savage when he went afield. Herb came back with targets from his expedition to the range with the Savage, and as most of us knew, it came back with examples of wonderful accuracy for an inexpensive field gun.
If you want to get guns that will make others "oooh and ahhh" at your treasures, then go ahead and get a used classic. But if you want something that is accurate and reliable, along with available ammunition and probably the lowest cost in the end, get an IOF .315 or .30-'06 and be done with it. I'm sure your range results will echo such a decision.
Also, go back and review the African magazine articles Brother Vikram has posted for us. The high cost British rifles are the stuff of legend, even to this day, but the people who had to live and survive out in the bush were using little 6.5x54 M-S pop guns and getting the job done. The theoretical differences between a .315 or .30-'06 on one hand and a .318 WR or .333 Jeffrey on the other may actually exist, but I am sure that you will get the job done with any of the choices. Whatever drawbacks you must accept with the .315 or .30-'06 compared to the others will be more than made up by buying extra ammo from the differences in price and spending more time at the range.
Those exotic cartridges of old are wonderful things for wealthy hunters and gun owners, or avid collectors to discuss and even shoot. If you fall into that category, then my advice to you is simple: just get what you want; get what appeals to you. If, on the other hand, you have a budget to be concerned about and you must nail what you are shooting at, because you are on the hunt of a lifetime, leave the theorists who are gathered around the internet's warm stove in the corner to debate infinitesimally minute theoretical advantages of super cartridges or those of the hoary legends of yore, and get a new gun for which ammunition is readily available.