I have taken several Elk (cows and bulls) with the following calibers 243, 30-06, 270 WSM and 300 WSM. The first cow was with a 243. The shot was about 100 yds. I fired the first shot and the cow appeared as if it had not been hit. I fired a second and the cow dropped in it's tracks. Upon closer inspection the first shot was right on target and the second shot was less than 2 inches from the first. Shot placement is everything and the 243 worked for me on my first Elk. However, Elk are extremely strong animals and I now would recomend nothing less than a 270 cal bullet (160gr Nosler Partition) or preferably LARGER. The only time the larger calibers are going to be felt are at the range. During the hunt, in the heat of the moment, you are going to tell your buddies you thought you were shooting a 22. I don't care if your shooting a 338 or 416 you will not remember the recoil. The most painful part of Elk hunting is drawing the tag!