When hunting elk with a rifle, shooting distances vary widely depending on the topography and vegetation you're hunting. The size of elk also varies. Bulls are bigger than cows; and mature, fully grown bulls are huge. None require field artillery, but a mature Rocky Mountain bull might weigh 800-1000 pounds, four times the size of most mule deer bucks.
I'm not suggesting that elk rifles should be four times more powerful than deer rifles, but elk are tough. There are dozens of good elk cartridges, with choices depending largely on the distances you intend to shoot, thus dictating the bullet energy you need to project. Foot-pounds aside, I think elk-sized animals are better taken with heavier bullets than are essential for your typical deer round.
My thoughts are this, the .25-calibers, limited to 120-grain bullets, are too light for bull elk. Modern 6.5s, whether slow like the Creedmoor or fast like the PRC, are limited to 140-grain bullets, also light for elk-sized animals. Adequate, but be careful and watch the distance.
The .270s are similarly adequate for elk…with caution. Again, bullet weight. Traditional .270s are limited by 1:10 rifling twist to 150-grain bullets. Okay, but minimal. The “new” .270s (27 Nosler and 6.8 Western), with faster twists and bullets up to 175 grains change the game. I'm convinced these new, heavy bullets elevate the .270's performance on larger game: Similar to the 7mms with like bullet weights; and exceeding the capability of any 6.5mm.
What's best for you depends on the distance you intend to shoot, based on where you hunt. I've had unsuccessful elk hunts, but I've never lost a bull, so my choices have worked for me. If I were planning a rifle elk hunt, these are cartridges and calibers I would consider, across the gamut of elk hunting conditions.
ALL-AROUND: START WITH A .30-06
Not exactly modern, not sizzling, hot or sexy. The old .30-06 remains an awesome elk cartridge. The .30-06 is the most powerful cartridge ever adopted by a major military. Although decisively effective, this means that it is overpowered for deer. As an elk cartridge, the .30-06 still shines. Recoil is stout, but substantially less than any magnum .30.
I think a .30-06 with 180-grain bullet offers about the same performance as a 7mm Remington Magnum with 175-grain bullet. Yes, the 7mm bullet flies better and can be pushed a bit faster, yet the .30-caliber bullet has more frontal area, dealing a harder initial blow. Because of lower pressure and achieving full velocity with less powder, the .30-06 has less felt recoil than a 7mm Remington Magnum.
The .30-06 may not be an extreme range cartridge, but it is capable for the shooting most of us would do. Certainly, out to 400 yards, no elk can stand up to a good 180-grain bullet well-placed from a .30-06. Not so long ago, I shot a nice Montana bull from the top of a ridge, down onto a little bench at 350 yards, 180-grain .30-06. Sure, I had to consider the drop and adjust for the downhill, still not a difficult shot, and the bull went nowhere.
OPEN COUNTRY: A MODERN 7MM
The 7mm Rem Mag is certainly adequate for any elk, especially with heavier bullets. No doubt I've angered all of its fans by comparing it to the old, slow .30-06. Work the numbers, compare for yourself; at moderate ranges differences aren't that dramatic. I used a 7mm Rem Mag for years, great cartridge.
Again, I believe frontal area matters. So, I don't believe any 7mm hits as hard as a .30-caliber. That said, the .284-inch bullet has two advantages. First, 7mm bullets tend to have better aerodynamics, so they will strut their stuff better at longer ranges. Second, since .30-caliber bullets must be even heavier to compete in the Ballistic Coefficient (BC) race, a magnum 7mm recoils significantly less than a magnum .30.
So, in open country, a fast 7mm has tremendous appeal. The 7mm Rem Mag has slipped in popularity, but with today's off-the-chart BC bullets, it is still a fine choice. However, if I were in the market for a fast 7mm, I'd look at one of the new unbelted cartridges designed for these bullets. With 7mm bullets now up to 195 grains, I would barrel it with 1:8 twist, vice the old 1:9 7mm twist. The primary example right now is the 28 Nosler, but 7mm bullet development continues, and I predict cartridge development will keep pace.
LONG-RANGE: A FAST .30
The elk offers a huge vital zone. With yellow bodies and bright rumps, in open country they can be seen at vast distances, making them a classic long-range target. I'm not convinced this is a good thing. At extreme range, hits or misses may not be apparent, and in the late afternoon it will be dark long before you get there to look.
No matter, people are shooting at elk at longer ranges, and today's rifles, optics, and bullets will get there. Because elk are so tough, the farther the shot, the harder you ought to hit them! Ideally, something like the .338 Lapua Magnum makes sense but, realistically, that is too much recoil. So, next best thing: If you're serious about longer shots on elk, man up and use a fast .30 with today's heavy, low-drag bullets, 200 to 225 grains.
They don't start as fast but with better aerodynamics, they'll pass lighter slugs at mid-range, and hit way out there with more authority. The .300 Win Mag is the world's most popular magnum. Still a great cartridge, as is the .300 Weatherby. I have both and have taken all of my “fast .30 elk” with them. However, if I had it to do over, I'd get a .300 PRC. Not faster, not always more accurate, but designed around modern bullets…which really do offer a long-range advantage.
IN THE THICK STUFF: A BIG LEVER ACTION
Not everybody has embraced the rage for range…and not all elk are found in open country. Some of us hunt still-hunt elk in black timber and on brushy lower slopes. Bugling rifle hunts aren't common, but they still exist. In these scenarios, shots are likely to be close and fast, and a bugling bull is pumped with adrenaline. Always, the idea is to hit a bull as well as you can, but you want to hit him hard.
Any rifle/cartridge adequate for elk at long range is also adequate up close, but my concept of a thick-cover elk rifle uses a heavy, large-diameter bullet, without concern for flat trajectory or extreme velocity. The classic was, is, and remains a lever-action chambered to something larger than .30-caliber. The old archetypical big-timber elk rifle was the Winchester M71 in .348. They are still out there but getting scarce. Hell, I've had at least one for 40 years. Another desirable choice is the also-scarce .358 Winchester, and I took a fine Colorado bull with a Marlin in .338 Marlin Express, a great cartridge. A couple of friends swear by the .444 Marlin for hunting elk in oak brush.
All good choices, except: Any rifle used for elk must wear a scope, because of low-light situations, and the need to find a hole through foliage. So, the most likely candidate today is a modern .45-70 lever-action, either a Marlin or Henry in the popular “guide gun” configuration, short barrel with easy scope mounting. With such a rifle, we are expecting a shot at less than 100 yards. With modern loads the .45-70 has 200-yard capability, and no issues about hitting an elk hard enough.
ALL-AROUND CHAMP: .338 WINCHESTER MAGNUM
Close or far, thick timber or wide-open, the .338 Win Mag is an elk cartridge! I have tremendous respect for elk. I want to hit them well, but also hard…at any range. With greater frontal area (than a .30) and heavy bullets, the .338 will do this. Although perhaps not an ideal “extreme range” cartridge, the .338 shoots surprisingly flat.
The problem with the medium magnums (over .30 and less than .375): There are few to choose from, and only the .338 is genuinely popular with a robust selection of loads. I had a long and happy love affair with the 8mm Rem Mag. Wonderful elk cartridge, so is the .325 WSM, but they're not common. I could go for one of the several faster .33s, but I've tried most of them. They shoot flatter, but they kick me into next week. So, for an all-around elk-thumper, I've gone back to the .338. Recoil is stout, but manageable. For big bears, I prefer 250-grain bullets, but for elk I stick with 200 to 225-grain bullets. They shoot flatter, kick less, and with the great modern bullets we have, they do the job!