My $.02...

1) Texasimport is right: 500 yards is a long damned way, and shooting there consistently is tough for the best of marksmen

2) bigbulls is right: a .30-'06 will kill elk at that distance, but you'll need to nail the shot placement. See #1.

3) Texasimport is right, again: a 2-7x scope might be found wanting at that range.

I'm thinking you can get closer than 500 yards, & you should certainly TRY. I don't know what conditions you'll be hunting in, but you might be surprised at close you'll get: after all, many bulls fall to guys with bows every year. I was in BC last Fall, & the guides said there are many shots at 10 to 30 yards in the black timber they've got.

I'd suggest upgrading your scope, if not in magnification, then in quality. I just replaced a VXII with a Zeiss Conquest, and was "wowed" at the difference in brightness & clarity. Given the expense of an elkhunt, & the rarity with which many of us get to try our hands at it, why not put another $300 to $400 in a kick-a$$ scope? You can't hit what you can't see.

As for bullets, I'd go 165 grains to 180 grains, with the latter being preferrable. Premium makes are what you want, such as NP, Scirocco, Accubond, TBBC, Interbond, Barnes, etc. Get out to the range now, find out which ones your rifle likes best, then get lots of practice with those.

Good Luck,

FC