Dao hit the nail on the head. Light and medium caliber double rifles are very common and popular, just not in North America. I would be willing to place a small bet that the type of double rifle being produced in the largest numbers today and for the past 15 or so years would be a O/U in 8x57jrs, or perhaps 9.3x74r. They are very commonly used on driven game hunts in Continental Europe. Also they cost a bit less over there, and bolt action rifles tend to cost a bit more, so the price differences is not as great as it is over on this side of the pond. On most of the driven boar hunts I've been on I would say the number of hunters with double rifles can be as high as 70-80%.