I have a 300 since I bought it specifically to hunt elk. The locals I hunted with used 270s and 7mm's.

It's all about range. Hunting within 350 yards or so? That 270 will work just fine. Planning to practice to shoot further? Think 7mm or 300.

Don't plan on the elk necessarily dropping as quickly with a 270....but place the shot like it's your job to do and they will fall.