I've heard the same argument about resident elk hunters here in Montana for decades: We can get by with smaller cartridges than non-residents because we have all season to hunt, so can "pick our shots."
This is mostly BS. While a few Montana residents hunt the entire season, most have jobs, so end up hunting weekends, when most other hunters are out. Unless they're lucky enough to own some elk-suitable land, or know somebody who does, they hunt public land like everybody else.
We have a 5-week rifle season, except in certain back-country areas that pretty much require horses to access. As a result, most residents can hunt five weekends, which means 10 days--IF they don't have something else they must do for part of the weekends. Some take a few days off from work to hunt, but the majority just make do with whatever Saturdays and Sundays they can.
Since they have limited time, and usually end up hunting where most other people do, their chances at elk are often fleeting, or take place in timber where the angle isn't ideal. As a result, few resident hunters pass up half-decent shots at a legal elk.
Non-residents usually hunt for at least a week, and often for 10 days. They often hire an outfitter, who has horses for taking them deeper into public land, or leases private ranches where pickups are often used. Hunting pressure is much lighter, especially on private land, where a lot of elk move after the first few days of hunting season, due to pressure on public land.
I have hunted elk in all those ways, though most has been foot-hunting on public land. In general, the easiest shots come on private land, though the early back-country public-land hunts can also be easier, because they start during the rut.
Twice when hunting private land I've seen 30-some branch-antlered bulls on one mountainside, a week or two after the season opened, and they lingered at least an hour after legal light. You NEVER see such large numbers out in daylight on public land.
In other words, non-resident elk hunting is often far easier than resident elk hunting, with far more options for "picking shots." Yet many non-residents firmly believe they simply must bring a .300 or .338 magnum, rather than the .270's, 7mm magnums and .30-06's used by many if not most residents.
The two bulls I've killed when I've been lucky enough to hunt private land during rifle season, by the way, were standing close to broadside, in the open, at 250 and 150 yards. Both were 6x6's, taken with a .30-06 and a 7mm magnum.
It depends on the specific situation. Most people hunting brown bear aren�t hunting for meat. I know a few Alaska residents who hunt brown bear fairly casually because they can go several times a year or even several times in a month. I can go once in about every four years.
Elk hunting is an amazing feat. The big ones weigh about 3 times that of a big adult male human. A 5.56mm 55gr round going 3,000+ fps or so is about right in the sweat spot for such a human animal. For a mature elk weighing 600 lbs, a bullet going similar speed at about three times the weight (say a 7mm appx. 165gr going about the same speed�as far as rifle bullets go) seems about ideal. If you�re going after a hard-to-kill animal weighing possibly twice as much as the 600lb elk, you might want to go a little heavier, say at least 250gr or so. This doesn�t mean that other options won�t work well at times. It�s just that, as the targeted-game keeps getting bigger, you might want to consider going with a bigger bullet, if it�s not a problem (e.g., through practice). I�ve had a range partner load my .340 and .375 without telling me (intentionally) whether there is a round loaded. When there is not, I click and don�t flinch. It took some practice to get that way, but it�s not nearly as hard to do that as hiking 30 miles on an elk or sheep hunt in the mountains. It�s not that hard if you try.
