As others have mentioned, the old cartridges - particularly those of military origin - have proved themselves the world over. Given the prevailance of the .303 during the heyday of the British empire and it's presence in such game rich lands we can only guess at the undocumented service it has seen. Along with that which we know from record and the much improved components availble today, it's value as a hunting round cannot be discounted. Are there more suitable calibers for specific game? Assuredly. Along with the 30-06, 7x57, 8x57, 6.5x55, 7.62x54R, etc. the 303 is a classic capable of any but the largest and nastiest of game. Not to discount such as Bell's .275 "elephant rifle" or it's use by Harry Selby's 14 year-old daughter Gail to take her own jumbo 30 or so years ago.

Personally, I love "the old ones." Would I buy or build a hunting rifle in .303? YES! In fact it was one of the final three calibers I considered for an upcoming project. All three centuarians. Much more important than the specific caliber is knowing it's limitations and staying within them.