welcome to the site
since odds are your not from the USA, I am going to say, it might come down to what guns are available to you? and not knowing what they are, be rather hard for me or most likely anyone here in the USA top recommend a exact make model rifle for you!
if you want to do a search to read up on things like elk hunting and the rifles and calibers used for them, that might get you a lot of basic info on picking a caliber,a s I gather them species your after will be about the same size as Elk, here in north america, and there is NO shortage of info on calibers for them and rifles used !
also keep in mind that when using a rifle, it also has a lot to do with how the rifle fits YOU
as what rifle I feel is best and fits me best might NOT fit you best and thus, you will never like it all that much,a s to one that does fit you
same with the design of things, what I like you may not
so there is NO such thing as a BEST rifle that fits and is liked by all!
and why they make so many different models and well calibers too
as again, there is NO perfect caliber either
you do need "X" amount of speed and energy in a bullet at "X" range to make clean kills, and there are , again, NO shortage of info on the world wide web to read and learn about that , which you can use to pick a caliber/rifle combo
best of luck to you!