Most any 50cal or larger will work for elk, even moose. The question is, at what range you want to shoot them?

The Apex is a very nice rifle, especially at that price new. The one I bought my son shoots under 3" at 200 yards with 130gr of Pyro pellets and a 250gr ShockWave. Sighted in 2" high at 100 puts it about 3" down at 200. And this is the first load I tried so It should do better with a little tweeking.

What I would suggest is go to a local dealer and try each of the models your interested in on for size. Find one that fits best and you will be happier than just buying sight unseen.

Good luck and ask any questions you have, there's plenty of knowledge and opinions around here.