I've never had to opportunity to hunt elk, but a 280 will certainly shorten the like span of a bull mose in a hurry. Shot placement always critical regardless of calibre. http://www.chuckhawks.com/280Rem.htm
280 Remington shooting 160-gr. Nosler AccuBonds or Partitions is great elk medicine. If this fine cartridge had been introduced 3 years earlier, then Winchester might not have even brought the 270 to market and we'd be ranting about the improved 280 Rem rather than the 270.
Others have offered up a sighting of roughly 2 inches high at 100 yards as a good sighting scheme. In my own experience I have come to favor a sighting of 3.5 inches high at 100 yards. This allows for the individual to hold dead-on (directly in the middle of the top and bottom) the animal out to roughly 350 yards.
Magnum calibers such as the 7mm Remington and 300 Winchester will extend this slightly. At 400 yards I hold directly on the backbone of the animal. The drop at this range allows the...