In the end its probably not really all that important which one you pick even, but it is still fun to discuss.
I am going to bang the " morals " drum one more time and then shut up . Yes it is fun to discuss some of the estoric points of calibers and terminal performance at a given range as long as one realizes that it is a rare rifleman who can make use of any supposed advantage one caliber may offer over another when you get out past 400 yards or so . The issue is that many feel they have an inborn ability to do such things as drive , handle recoil , guage range in an unfamiliar environment . Just how tall is an average fence post , or soapweed in a given pasture ( which are objects on the plains that may likely available to give " scale " to an animal ) As an instance i have seen folks brag about a 400 yard shot on a prarie dog that when a rangefinder is put to the shot it will read 250 and change . Now i am talking about good shots with experience enough to " know the rifle " but due to the lack of " scale " they will wildly mis estimate the range normally leading to misses or poor hits . On prarie dogs and to a lessor extent song dogs this is not a huge issue as a hit with a centerfire will usually be enough to anchor the animal and a miss is a miss . I see guys get the newest " thumpenboomer " for plains shooting and then due to recoil/ammo-cost/noise/time/lack of a place to shoot at range, ect.. not practice . They still however feel that they can " rifle " their way into long range field accuracy . Thus far we have not even spoken to doping the wind angle, speed , gusts ect, and its effect on both the trajectory and the stability of the shooter under field conditions .
Now that i have said my piece which can be summed up as something like " your better off passing on the shot and hoping for better later " . I will say that were i going to buy a rifle to " shoot across the canyon " with it would be either a 7mm mag or a 300 win mag . I have owned both in the past , and sold both as i found myself doing exactly what i despise , not practicing with the rifle enough . Nowadays i shoot either a .308 or an 06 for large game and just pass on the shots i suspect are marginal with my abilitys . This way i shoot year round ( i plink quite a bit with my truck gun which is normally a .308 ) and stay more current/confident come season . Just this am while hauling water to the cattle i happened to bag two coyotes using a coral post as a rest. The first at i believe a bit less than 200 yards and the second at a bit over 300 when he stopped to look back . I did not bother to pace off or measure the shots so the range is a somewhat realistic guesstimate . I wasnt then nor am i now concerned about the exact range , they did however fit into my abilitys and due to experience with the size of coyotes and cattle they were mingling with as well as my rifle i had the ability to " scale " the range and do a quick holdover from my zero for a successful set of shots . If i did not practice consistently there is a good chance i would have over estimated the range and shot over the back of the songdogs . Now i by no means am an exceptional rifleman, I just recognize my limits as well as the fact that caliber is not the answer to extending them . Quite possibly some lifestyle changes such as quitting smoking coupled with more aerobic exercise to get my breathing under better control would go a long ways tho . Once you pass 400 yards shooting becomes much more technical since even slight mistakes are magnified by range and will continue to be until we have something such as a functional lazer that literally will hit where the crosshairs rest at a given range . There are some amazing rifles and shooters out there that under ideal or near ideal conditions make some amazing shots. However even a sniper normally has a luxury that a hunter does not , he can prepare a " hide " to get as close to perfect as possible before he shoots ( not always but as a rule this holds pretty true ). The hunter however is presented with an " opportunity " shot more often than not , and if any rest is available it is likely to be improvised . By all means stretch your ability as a shooter to the limits you can archive, but at the same time realise that a new rifle , or new scope is not likely to be the answer to achieve hits in the real world tho they may work to a degree on the range.