Best Rifle and Caliber for Hunting in Colorado

Updated on January 15, 2017
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LJ Bonham is an author, historian, hunter, and firearms enthusiast who lives in the Rocky Mountains.


Legend has it there are three seasons in Colorado: football, skiing, and elk. Colorado has spectacular, challenging terrain and abundant big game animals. 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 animals.

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 which 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 water courses 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 require powerful magnums for a clean kill, even at longer ranges, although magnums will extend 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)

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 | Source

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, 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 under growth 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 sight lines 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 sage brush sea, with aspen along water courses. Again, great for spot and stalk hunting tactics, but the elk are wise to this.

Tree line 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 hunts above tree line, a light weight rifle chambered in a short magnum caliber, such as .300 WSM, is recommended.

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 | Source

Bottom Line

Colorado has no known grizzly bears and a limited moose population. Unlike Alaska or Montana, 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. The elk calibers listed above are also suitable for moose and black bear.

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 elk in the high country.


Typical 400 Yard Shot Across A Gully In The High Country

Questions & Answers

    © 2017 LJ Bonham


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        Cubefarmer 3 months ago

        300 Winchester magnum