Well I might add my 2 pesos worth here, and I might add there is some very interesting insight, But I will be as gently as I can I do not want to infringe on anyones point of view. But to place all practical matters at hand in truth, Make darn sure you can handle yardage out past 250. seriously... 500 yards is a far piece to shoot with any big game rifle. 22-250, 222 etc. are designed to do this. I am somewhat experienced in long range tactical shooting in Vietnam with a 308.
Two things that are really simple to figure out is ...can you handle a recoil of a 300 mag and 338?....and can you figure out what goes on with windege within 500+ yards because you could have up to 2-3 different cross winds and a down draft in some certain occasions. thus your shot, what you think is dead on can be up to 6" to a ft off......plus remember that a big game round is not designed to do what a sniper round is suppose to do.
It would be a big benefit to rely on marksmanship . I use a 340 weatherby for Brown bears and this is what a 338 is designed for, not for shooting into the next county. and believe me if you are going to take a chance and throw a big game built out with out having the marksmanship skills to go with it , your "hitch in your get along" maby be to much to handle for walking much distance looking for a wounded animal.
I have read many articles on long range shooting and some are full of BS. I know many who shoot wide open country and you are better off shooting smaller calibers than larger ones.
and many of the long range kills are shots of luck than pin point accuracy.
Yes I agree one should put many hours to shooting long range and you can't do this with big bore rifles, mainly because your shoulder would be like jelly in less than 10 rounds, and the expense would swallow up the common working hunter.
Most of my Black tail I have killed have been within 125 yards 270, 243 and 308. Mule deer one was approx 225 and that was killed with a 7mm mag. Elk My furthest was shot at approx 275 and that was killed with a 7mm mashburn super magnum.
My 340 weatherby has killed 2 brown bear and 3 Yukon moose. But understand you don't shoot to kill a brown bear on the first shot. You shoot a brown bear on your first shot to break it down so it don't eat you.
In my opinion if you Hunt 90% of your season in wide open country, learn how to stock and spend much time shooting in desert country. and do it with a smaller caliber rifle. and if your season is about ready to open, I am a traditionalist go for accuracy rather than power, I have the standard rifles 270, 308, 243, 7MM mag of 2 flavors and of course 340 for dangerous game.
I have seen more trophy bucks killed at long ranges with the 30-06, 270 or 280 Rem. loaded with 130-150 gr bullets. than anything else. and that has been through out New Mexico, Montana, Kibab Arizona, Oregon etc.
So in essence If you cannot move around much, don't go with a cannon built for breaking up bone and tearing up allot of flesh and blood vessels on Dangerous game, settle for a mild shooting piece that you can comfortably shoot and hit your target within 250 max.....because if you don't, you will pay the price in hobbling all over Gods creation looking for a wounded animal.