I've shot them straight through the heart (couldn't find the heart when field dressing) and have had them run another 30-50 yds, but the last elk I shot was a "high on the shoulder" shot and it went DRT. I pulled the shot (I'll admit when I'm off) because my pack straps were in the way, but the bull went straight down faster than I've ever seen one go down before. It wasn't just because I was using my 338 either, a good shot from my 30-06 would have had the same effect, sorry to say (the shot was around 85 yards or so).
