Before the advent of smokeless powder, hunters killed elk with cartridges now dismissed as unsuitable. The first small-bore, high-velocity rounds were in fact neither--at least by current standards. Compared to the .44-40 and .45-70, though, the 7x57 and .30-40 Krag employed slender bullets that moved at scorching velocities--over 2,000 fps.
Elk haven't changed much over the last century. New elk rifles have little in common with the iron-sighted dropping-blocks and lever-actions that ushered in the metallic cartridge and thumb-diameter greased lead bullets. My books, Elk and Elk Hunting, Elk Rifles, Cartridges and Hunting Tactics, trace the history of popular elk rounds and the evolutions of scope-sighted bolt rifles. One question they cannot answer is: What's the best cartridge for elk?
I killed my first elk with a Henrikson-stocked 98 Mauser in .300 H&H Magnum. It wore a 2 1/2X Lyman Alaskan scope. My handload of 70 grains H4831 pushed 180-grain Speers at nearly 3,000 fps from the 26-inch barrel. Had I never carried another rifle, my elk tally to date would likely have been very close to what it is. By last count I've used 30 different cartridges on these animals and have seen them shot with other loads.
Powerful, flat-shooting cartridges have become ever more popular for elk since Roy Weatherby announced his first magnums during the Second World War. The .338 Winchester, 7mm Remington and .300 Winchester Magnums always appeared among the top five rounds in my elk hunter surveys during the 1990s--and they've stayed there. So have the less powerful .270 and .30-06. Both are obviously adequate; longevity alone can't account for their celebrity status.
While short, rimless magnums have gained traction lately, they offer little, if any, ballistic advantage over their belted forebears. In fact, a good case can still be made for the likes of cartridges born a century earlier. In a 1939 survey of 2,300 Washington State elk hunters the .30-06 stood tallest among the six most popular cartridges. The others: .30-40 Krag, .300 Savage, .30 and .35 Remington, and .30-30 Winchester. All might now be classed as woodland deer cartridges by generations of hunters who've been led to think elk wear flak jackets.
They do not. Granted, they are tough animals, especially mature bulls. There's more difference in body weight between a spike bull or a cow and a big six-point than between a mature mule deer buck and the spike. You'll find any deer rifle adequate for young elk. Old truck-shouldered bulls take more killing.
Rules of thumb regarding bullet energy, though, put you on a slippery slope. There's no fail-safe formula, because field conditions vary. How far will you shoot? What level of precision can you guarantee? What bullet did you choose? I've been chastised for toting a .30-30 carbine and for recommending a 6mm to a young hunter. In both cases there were other options. While the .30-30 imposes limits I wouldn't endure with a .308 Norma, I've taken elk with it--including a big six-point. The lad with the 6mm made a one-shot kill--which he may or may not have achieved with his harder-kicking .30-06.