ORIGINAL: northslope nimrod

.270 good for elk? Nope! Many of my old hunting buddies used to use the .270. Most have switched now after years of elk getting away. Will it kill the elk? YES. Will you find the elk once it dies......probably not.
.243 for elk? My cousin used one the first year he hunted elk. I think he actually killed a four point. He shot it at about 80 yards. It then...luckily...ran straight at him and he shot it in the chest and it finally dropped. I use 180 grain soft in a 30-06 and I'm STILL nervous about dropping them. Last year I shot a 6x6 through the liver at 40 yards....I then shot him in the lungs as he ran twice more. Then I shot him in the neck and he fell. Then he ran again and I shot him in the neck and he fell dead. My point...even at close range... you may not hit the perfect vital spot.....The larger calibers hopefully will give you the added "shock" to drop him. The .243 is too risky...unless you like and stick to head shots.