the 270 wsm will def get it done on elk. I know guys who shoot 243 wssm for elk. as others have said its all about distance. guys kill plenty of elk with bows, but not at 800 yds. so, then you have to decide how far can you shoot in the area you hunt. if no shots are possible past 100 yds, there is no reason to get rid of your 270 win. if you can shoot out to 1000 yds, then you need a different cal. So yes, the 270 wsm can kill elk out to distance. now the question is can the rifle you chose do it? can the ammo? and can you? I would venture to say that most off the local sporting goods shelf, with basic factory hunting ammo are not capable of shooting accurately enough to hit an elk at 800-1000 yds. at least not reliably enough to ensure a first round hit, every time. heck that's a tall order with a custom rifle and hand loads. so, really look at what you can do in the area you hunt, what you are willing to do to ensure the rifle and ammo is capable of shooting, and you practice enough to be able to successfully engage an animal at the distance you want.
I know when I goto the range with my 6.5 saum, I always take a cold bore shot at 600-800 yds. cause that's what my hunting scenario will be. Ive spent a lot of time doing load dev and then shooting and trueing out my ballistics calculator to KNOW my dope is going to be perfect when it comes time.
just some things to think about