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Best Rifles and Cartridges for Hunting in Colorado

LJ Bonham is a semi-subsistence hunter, hunting magazine editor, and firearms enthusiast who lives in the Rocky Mountains.

The best overall choice for hunting anywhere in Colorado is a bolt-action chambered in a thirty caliber magnum.

The best overall choice for hunting anywhere in Colorado is a bolt-action chambered in a thirty caliber magnum.

Legend has it there are three seasons in Colorado: football, skiing, and elk. Colorado has spectacular, challenging terrain and abundant big game animals. The Centennial State is home to mule deer, elk, moose, black bear, pronghorn, bighorn sheep, and mountain goats. Which is the best rifle and cartridge for hunting in this amazing state?

Regulations, Regulations, Regulations

Colorado has minimum caliber, bullet weight, and bullet energy regulations. Big game requires at least a .24 caliber cartridge which generates at least 1000 ft-lbs energy at 100 yards. Minimum bullet weight requirements are 70 grains for antelope, bear, and deer; and 85 grains for elk and moose. These are the legal minimums, but many experts recommend at least 1200 ft-lbs impact energy for deer-sized animals and 1500 ft-lbs for larger critters.

Two Distinct Worlds In One State

Colorado is divided almost in half between the eastern plains and the Rocky Mountains. Each area has challenges for hunters and each is best suited to certain guns.

The "Flats"

Colorado’s population is concentrated along the Front Range in an urban belt that runs from the Wyoming line south to Pueblo. The primary game available outside the Denver metro complex is pronghorn antelope, although mule deer and some elk are found in rural counties where they eke out a living along the major watercourses which are lined with cottonwood trees and brush.

The eastern plains begin at the Bijou basin just east of Denver where they are rolling and interspersed with creeks. As they approach western Kansas and Nebraska, the plains turn flat with little to break up the horizon.

This area demands flat-shooting cartridges. Shots are often taken beyond four hundred yards. Most hunters rely on accurate bolt-action rifles, although hunting deer from a tree stand next to a creek lends itself to lever-actions, pumps-actions, or semi-automatics. The exception to bolt-actions is Browning’s BAR semi-auto. The BAR’s bolt locks up securely to the barrel like a bolt-action which makes it as accurate.


Best Plains Cartridges

Neither deer nor antelope requires powerful magnums for a clean kill, even at longer ranges, although magnums will extend the effective range further. Here are some recommended non-magnum cartridges for these animals.

  • .243 Winchester
  • .25-06 Remington
  • .260 Remington
  • 6.5x55mm Swedish
  • 6.5 Creedmoor
  • .270 Winchester
  • .280 Remington
  • .308 Winchester
  • .30-06 Springfield
  • 8mm Mauser (loaded to European specs)

For tree stand work on deer try these:

  • .308 Winchester
  • .30-30 Winchester
  • .348 Winchester
  • .45-70 Government

If a hunter wants to reach out a bit farther, the small-bore magnums are good choices.

  • .257 Weatherby
  • .270 Weatherby
  • All the .30 caliber magnums
  • All the short magnums up to .300 WSM
L-R: 9.3x62mm, .30-06, 8mm Mauser, 6.5x55mm, .308.  All good Colorado calibers.

L-R: 9.3x62mm, .30-06, 8mm Mauser, 6.5x55mm, .308. All good Colorado calibers.

The Tall Country

Colorado’s western half is dominated by the mighty Rocky Mountains. Colorado has the highest average terrain of any state and its mountains are synonymous with one thing: elk. While mule deer, moose, big horns, mountain goat, and black bear also call the high country home, it is the Prince of Stags which draws hunters from around the world.

Tough Customers

Elk are notorious bullet sponges, able to shrug off even solid hits as though nothing had happened. These animals see heavy hunting pressure which makes them paranoid and often semi-nocturnal. They seem to have a built-in four hundred yard buffer zone around them and seldom allow anyone to approach closer, although hunters skilled at elk calling can improve their odds.


A Unique Landscape

The mountains also conspire against hunters. They have little undergrowth unlike places such as Montana and Idaho. North-facing slopes are dominated by ponderosa pine mixed with aspen groves. There is significant space between trees, which makes good sightlines for hunters, but the elk can also see a long way as well. South-facing slopes, depending on elevation, are dotted with isolated pine clusters set amidst a sagebrush sea, with aspen along watercourses. Again, great for spot and stalk hunting tactics, but the elk are wise to this.

Treeline in Colorado is approximately 11,000 feet above sea level. During the early season, or if the autumn snows come late, elk stay high on the tundra-capped peaks and ridges and can spot hunters far away at which time they run down into the opposite drainage never to be seen again.

Best Cartridges For The High Country

Bolt-action rifles rule in the high country, and elk hunting favors hard-hitting, flat shooting magnum cartridges such as these:

  • .257 Weatherby
  • 7mm Remington Magnum
  • .28 Nosler
  • 7mm Weatherby
  • .300 Winchester Magnum
  • .300 Weatherby
  • .30 Nosler
  • .300 Remington Ultra-Mag
  • .300-378 Weatherby
  • .338 Winchester Magnum
  • .340 Weatherby
  • .375 H&H Magnum (loaded with low drag bullets)

For early-season elk hunts above the tree line, a lightweight rifle chambered in a short magnum caliber, such as .300 WSM, is recommended. For moose or black bear, the elk guns will do just fine, but you can these to the list, too.

  • .444 Marlin
  • .450 Marlin
  • .45-70 Government
L-R: .338 Win Mag, .300 Win Mag, .375 H&H.  All great Elk cartridges.

L-R: .338 Win Mag, .300 Win Mag, .375 H&H. All great Elk cartridges.

Big Horn Sheep and Mountain Goat

Colorado's other iconic animals are the Rocky Mountain bighorn sheep and the mountain goat. They are elusive and live up high almost year-round. If you want one, you'll have to climb, climb, and climb. Then sit in the snow and wind for hours while you glass twelve to fourteen thousand-foot high ridges and peaks a mile, or more, away. If you spot them, you're lucky indeed to close the distance below 500 yards. This is a special hunt that requires special equipment.

Here, the lightweight mountain rifle is king. Most such guns are built on short actions to keep their length and heft to an absolute minimum. Into this specialist rifle, you'll want to put a round with a laser-like trajectory that packs a solid wallop 500, or more, yards down range. Both sheep and goats are tougher than they look. They will kick and thrash until they fall off a 2000-foot drop if they are not anchored with a good, decisive shot. These are the best bets for cartridges.

  • .260 Remington
  • 6.5 Creedmoor
  • 7mm-08 Remington
  • .270 WSM
  • .300 WSM/.300 Remington SAUM

Bottom Line

Colorado has no known grizzly bears and a limited moose population. Unlike Alaska, Montana, Idaho, or Wyoming, Colorado hunters need not carry a rifle powerful enough to stop a charge from either animal. If a hunter is pursuing deer and elk, just take the elk gun, it will get the job done on mulies as well.

If a hunter is limited to just one gun, the best overall choice for hunting anywhere in Colorado is a bolt-action chambered in a thirty caliber magnum. It will shoot flat enough for the plains and hit hard enough for the high country.

This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

Questions & Answers

Question: Where does the 7mm WSM fit in for all around caliber?

Answer: Same place as 7mm Rem. Mag. A good choice for anywhere and anything in Colorado.

Question: Can I hunt pronghorn with an SKS?

Answer: Sure. Use a good bullet such as PPU's soft-point, Nosler Ballistic Tip, Hornady SST, or Sierra Game King and hit 'em in the vitals at a reasonable range.

Question: Is a Marlin .357 Rifle legal in Colorado?

Answer: I suggest you consult the Colorado hunting regulations as minimum caliber and energy rules for big game hunting change from time to time as technology advances.

Question: How much orange clothing do you need when you hunt in Colorado?

Answer: Consult the latest Colorado hunting regulations as these requirements can change.

© 2017 LJ Bonham


Cubefarmer on January 22, 2018:

300 Winchester magnum