Shots to 500yds on elk...I hear a lot of guys from the east talk of such things. Generally it is guys that have never hunted elk, and don't really know how far 500yds is. Elk are big, and thus have a big vital zone to hit, but bad shots I've seen (and done) at elk have been largely because of nerves (elk fever). Elk aren't hard to kill if you hit them right, but they will run for miles up and down mountains and valleys if you hit them poorly.
My advice: don't plan on taking a 500yd shot, particularly if you are fairly new to rifles. Plan on taking a maximum-point-blank-range shot (for the 30-06, about 300yds, if sighted in for a 260-270yd zero). Don't shoot farther; get closer. The time to start shooting that far at animals isn't on elk in unfamiliar country. Plan to hunt, and enjoy the hunt. Elk hunting is addictive!
Regarding your ammo choices, I've used the Berger 185's in a 30-06 quite a bit with a MV of 2730, and have never failed to have an exit on deer or elk broadside and quartering from 70-450+yds. I'm confident in that bullet (and many others) to handily do what is required. I've been around elk killed with a few various 30 cal Barnes bullets and with several weights of Accubond from the 150's in a 308 to the 200's out of a SAUM. They all seemed to work well without failure. I personally prefer "softer" bullets of heavy-for-caliber weights when hunting where elk are a possibility. Some guys prefer the opposite.
My young nephew killed his elk this year with a 243 (in a Savage Axis!) and Hornady 105 BTHP, an old cow at 300yds, off sticks. The first bullet squared her shoulder on a slightly quartering shot, busted the humerus, and didn't get into the ribs. Shot two passed through the ribs and out, and was likely the clincher. He finished her in the neck because she was still on her feet. It doesn't take a cannon, but you have to know your limitations. She was the second-largest cow I've ever seen killed. I suggest that in whatever situation you find yourself when the shooting starts, keep shooting until the elk is down. Admiring a shot is for TV shows.
