I don't have the actual sales figures (rifles, dies, factory ammo sold?), but would suspect the 30-06 to be the most popular and wouldn't be afraid to put money on it either. Even here in Alaska where some of the other chamberings make a little more sense, the '06 is the top of the heap based on a report from Alaska Department of Fish and Game. I would expect it to be the same in every state of the union as well.