I have to agree with the others that have posted responses. I would use the 270 and stoke it with premium ammo/bullets. There are any # of controlled expansion loads for the 270. To name a few, Nosler partition, swift A-frame, fail-safe, Barnes-X, & others. I would use 140 gr as a minimum weight and 150 would be preferable.

On the other hand if you want a new rifle I would look to the 300 Win. Mag. or the 300 WSM. Out of these I would fire a premium load in the 180 gr. class. Buying a 30 cal will still require good shot placement to take an elk. If you buy a new rifle practice and become proficient with it before you take it hunting.