I've used my Remington 725 .280 Rem. to kill elk. My handload is the Nosler Partition 160 gr. bullet, in front of 54 grs. IMR 4350, standard CCI Large Rifle Primers. Chrono'd at 2872 FPS, 22" barrel. I've had two, one shot kills on bull elk, neither being more than 225/250 yards.
If you shoot accurately, and use a good bullet, the .280 Rem. will do its job on elk.
FWIW. L.W.