The question isn't "will a 7mm-08 kill elk", since clearly, under reasonable conditions it will. The real question is this: why use a 7mm-08 when you have a .30/06?

i couldn't agree more! with the price of brass and bullets today, why not put the price of a rifle (if you don't have the 7mm-08 already) into components for the .30-06?
i'd expect either a 165 or a 180 gr' Hornady spire point.....if it's accurate out of your '06......to knock over the largest bull out there with good shot placement at 300 yds'. if you can handle the recoil and can assume a proper field-shooting position then i think the '06 will do it at that distance with one of those bullets or with one of the same weights in the more-expensive Nosler variants.
if the barrel length and its related velocity, with a proper bullet, on the 7mm-08 are not 'enough', you'll be disappointed.
good hunting and shooting to you,
ss'
Because, because, because...
Actually, that is the same question that my wife has lately.
My 30-06 is a Win. Mod. 70 Classic Sporter with a David Miller stock (Limbsaver recoil pad) in NRA Excellent condition. Same with the 7mm WSM Win Featherweight in Excellent condition, with a Limbsaver and a Williams Guide Series Muzzle brake. Now that Win./U.S. Repeating Arms is out of business, I am sorely tempted to relegate the weapons to the safe, and pick up a new Ruger Hawkeye to use.
While I am still getting out into the field on a regular basis for my doctoral research (chasing mule deer on the North Rim of the Grand Canyon

), after 5 operations in my abdomen and back in the past 2.5 years, I watch the recoil. So, while I know the .30-06 will work well, with my medical history and the way that I periodically feel crummy, switching to a 7mm-08 isn't a proposition that is out of the realm of possibility.
So, please, give me all of the feedback that you can. I will place it into the hopper and consider everything before I make a decision.
Thanks,
Matt