Well you said you can kill an elk with a 243, my neice(great shot with that gun 2) shot an elk at 15 yrds and we never found the bull, and my brother in law hit the elk(same elk) with his 30-06 and the biggest drop of blood we found was a dime size. So i would say that, and with the 30-06 for elk it wouldn't be that great of a gun for elk but it would work if you can put as much lead as possible in it. But if you want a gun that will take an elk down at 300 yards i would get a 7wsm,300, 338wm. (THIS ALL HAPPEND IN KREMMLING COLORADO)