With accuracy the only criteria, what would you all recommend for the best .308 bullet for 500yd shooting
in a Rem.700 Varminter?

Sierra 168 grain HPBT on top of N-550 From 40.7 grains to 48.9 grains and Remington 9-1/2 Primer

What's the cartridge and how windy is it?

In any case I would look at the Sierra Matchkings.

Junglework
If you are just paper punching the Sierra 168, or the 175 matchking.
If you are shooting varmints or animals up to the size of, say, Caribou I would try the Nosler Ballistic Tip in 165 or 180gr.

Junglework,
This is another vote for the 168 grain Sierra Match King bullet. I've tried several powders in my .308 Win., The best accuracy came with H-Varget and CCI #BR2 primers.Good luck.

For Med Game in the 308 Win:

165 Sierra BTHP
VARGET @ 46.0
CCI BR-2 Primer
Lapua or Win Cases

COL: 2.80"

I've had great success with the Sierra 168 MatchKing in my WinMag. I use 70gr AA3100 and WLRM primers. Consistenly 1/2" at 100 yards. Supposedly (no chrony) good for 2900fps.

If you want to shoot to 500 yards you might try the 190gr version. It should do better in wind and, in a WinMag at least, shouldn't give up too much in muzzle velocity. I have not played with this one yet, but I figure best accuracy should come with about 2800fps, though I could probably get close to 3000fps.

Good luck.

A-Max's, higher quality and consistancy than any of the Sierras. Accuracy is TOPS!! Compare them for yourself.