This post will answer your question! First off, I will certainly echo what flags has just posted, but will put out a little more on ballistics for the 30-06. As an example of a good elk bullet I picked the 180 grain Remington using a Swift Scirocco bonded bullet with a ballistic coefficient of .500 out of their chart. That bullet starts out at 2700 fps and is still traveling at 1878 fps at 500 yards with 1409 ft/lbs of energy. With a 200 yard zero that bullet has dropped 8.3" at 300 yards, 23.9" at 400 yards, and 47.9" at 500 yards. Conventional wisdom from the old time experts has essentially stated that a bullet should carry 1500 ft/lbs of energy at POI for a humane kill on an elk and down around 1000 ft/lbs for deer. Some now say it takes less than those numbers, but let's go with the 1500 ft/lb figure. Thus, using that number your max distance with that bullet would be 400+ yards IF you have the equipment and expertise to put that bullet in the kill zone EVERY time at that distance. Obviously that is why flags made his opening comment regarding the power of a 30-06 and that 95% of people have no business shooting at an animal at the distance where it is still quite effective. You mentioned in your post about not knowing the distance to the elk you passed on. That is the main reason you need to know precise distances when you start getting out to the 300 yard and longer distances, as you can see the huge drop of this bullet in my post when it goes from 300 to the 400 and then to the 500 yard distance. IMHO a person should never shoot at any distance that is much beyond what they have been practicing at on the range and at which every bullet will go into the vital of an animal. Every elk that has been taken with the people I normally hunt with in Wyoming has been from around 200 to 350 yards and the closer we can get for a good shot the better!