The .257 Roberts use to be a much more popular hunting cartridge. From what I have informed, the .243 Winchester changed that. IMO, the .257 Roberts and more so the .257 AI are a better .257 round than the 25-06. They use less powder and performance is not much below that of the .25-06 - especially the .257 AI. Some claim they are also more accurate. It is hard to argue the efficiency and accuracy of a cartridge based on the .308 Win case.