Jabali: I've done a fair amount of testing of various .303's in my ballistic media. PM me with your address and I will mail you some results. If you like and have the ability, maybe post the results here? I posted them all on the old gunboards forum but I forgot to repost them on the new board after the old one went down. In a general sense, in the test media, you won't find anything dramatically different between the .303 and many other rounds like the .30-06, though that round and others have somewhat flatter trajectories and due to their higher velocities will carry ".303-level performance" out a little further than the .303 does. The .303 has no mystical properties, but its effectiveness cannot be denied.

A vast number of devotees have a vast amount of good to say about it based on a vast amount of experience.

When I hear a fellow say the .303 ain't no good I immediately ask "I bet you think the .30-30 won't kill deer, too."