Many hunters consider elk to be one of the toughest game animals in North America. Volumes have been written about their durability and rugged construction and generations of hunters have told stories around the campfire about the big one that was too tough for an ordinary rifle to bring down. Elk have inspired cartridge and bullet debates for decades — leaving some hunters thinking they need heavy artillery to penetrate the testosterone-thickened hide of the beasts. But how tough are elk, really?