RE: Need best caliber Opinions.
how far will your shots be? will you hunt elk more than once in awhile or once a year?
if you spend most of your time hunting deer and with a ocasional elk and your shots are under 300yds i would compramise between the 280rem and the 300win.
just go with the 30-06sprg. best of both worlds without the extra kick. better selection of bullets premium and non. ammo is every store and cheap.you can get some of the accesllorators up to 220gr. bulets. even though 180gr. will be more than enough for elk.
if you don't want a 30-06sprg. i would personally go with 300win mag since the ammo of the 280rem are alittle bit harder to find.