Don:
Before I started hunting elk in the wide open country, I never even considered a magnum rifle. My goodness, the numbers of elk that my dad, my brothers, and myself killed with .270s and 30-06's. Back in the 1970's we did consider the .257 Roberts marginal, but with the bullets available today even the .250 Savage and .257 Roberts will dispatch an elk cleanly at what you call "sensible distances" with a decent hit.
When I became fortunate enough to be able to shoot a bull and an additional cow within an hour from my house, I used a 30-06 for years. Then I started extending the ranges out of necessity due to terrain. I have taken many elk beyond 400 yards. That's when I stepped it up a notch. I went to a 30-338 until I got tired of the recoil, then I dropped back to a 7mm Rem. Mag.
When I shot the barrel out of the 7mm Mag (trying for the 1000 yard club on p-dogs) I stepped back to a 6.5x55 Swede in a Sako rifle shooting 140 grain Accubonds. The cartridge worked fine out to the longest shot I took, 300-350 yards. I then went to a long range set up on a factory rifle (Savage) in 6.5-284 just for fun. The rifle has a 24 inch barrel (what was Savage thinking) and I can only get the same velocities as I got out of the 6.5x55. In both guns I use Lapua brass and load them plenty warm. I have shot several elk between 350 and 450 yards with the 6.5-284. The rifle works well and so would a modern rifle in 6.5x55 using hand loads.
The rifle I now use for the majority of my hunting, unless I am pushing the distance, is a 7mm-08 with 120 grain Barnes TTSX bullets. I have only shot a handful of cows with that rifle, out to around 300 yards, and all have been complete pass throughs in the boiler room. Dead as a wedge. I think any thing in the lines of a 25-06, .260 Rem, 6.5x55, 7x57, .270, 7mm-08, .280, etc. is enough rifle for elk hunting, if the hunter is willing to only take a decent shot at sensible distances. Truth be known, many elk hunters really are over gunned for the job...but there is no such thing as too dead.
Still, I do recommend a larger caliber for those hunters who want to shoot at extended distances. As a guide, I know that it is darned hard to get a client to pass on that trophy of a lifetime if he tknows he can make the shot. It's also hard to get a client to pass on a quartering shot if they feel the critter is going to get away. Yeah, I know a bad hit on an elk is a bad hit whether it's with a .250 Savage or a .375 H&H. I just feel like if a person is competent with a magnum rifle, they might as well stack the odds in their favor. For the most part, I think we are probably pretty much on the same page.
Only thing I don't like about mine is that it's a big, heavy rifle to carry in rough country. I'd rather be shooting it, though, on something like elk. All I've taken with mine is deer, one mulie across a New Mexico canyon and a few whitetail in the trans pecos of West Texas. I bought it thinkin' I'd get to go elk hunting when all I had was a .257 Roberts at the time. The elk hunt never happened, but the rifle and cartridge is impressive. Reports of its massive, inhumane recoil are greatly exaggerated. It ain't THAT bad even off the bench, not any worse than the .30-06 everyone on this board thinks is the cat's meow.
