What Is The Best AR-15 Caliber Round Hunting


The AR-15 rifle needs no introduction and is most likely among the most popular firearms today. In America alone, more than five million AR-type rifles have been sold since the 1970s. Colt owned the patents to the ArmLite-15, but the patents expired in 1977. Resulting in over 500 rifle manufacturers now offering an AR Type of Rifle.

The best AR-15 caliber for hunting depends on the game species you’re hunting. The following calibers are the best choices for the average hunter using an AR-15 type rifle for these applications:

  • Best Overall: 6.5mm Grendel
  • Best for Deer: 6mm ARC
  • Best for Elk: .450 Bushmaster
  • Best for Hogs: .350 Legend

AR 15-type rifles are available in hundreds of variants, many specifically designed for hunting applications. Choosing the right rifle for your application is one part of choosing a hunting AR. Selecting the right caliber is as essential. Read on for the right caliber choice!

Best AR-15 Caliber For Hunting?

Choosing the best-suited AR-15 type rifle comes down to personal taste. The choices in stock design, rifle surface finishes, barrel lengths, optic sights, and accessory attachments all play a part in formulating the ideal rifle for your needs.

Caliber choices vary widely for the AR-15 type platforms; however, when choosing a caliber for general game hunting, a compromise needs to be found to cover as wide a field of hunting as possible, especially if you only own one rifle for the purpose.

The most popular caliber offered in the AR-15 type rifles is the .223 Remington and 5.56mm Nato. Although great to shoot in terms of recoil, its effectiveness falls short of a hunting cartridge. Its downfall is its combination of high velocity, 3000 ftps plus and the light bullet weights on offer.

Poor bullet penetration, tiny wound channels producing a poor blood trail, and excessive meat bruising are all traits that have resulted in the .223 Rem being disallowed from hunting deer in many States.

The 6.5mm (.264) cartridges have gained an enviable reputation in the sport shooting and hunting fields. Initially introduced in Europe and earning their stripes in the Mauser rifles of old, in calibers such as the 6x45mm, 6.5 x 55, 6.5 x 57, and others, their popularity spread worldwide.

As time marched on, many different cartridges were developed around the 6.5mm bullet, given its inherent accuracy, excellent momentum, superb bullet coefficient, and excellent penetration on game in the hunting field.

The 6.5mm Grendel is our choice for general hunting. This 6.5mm was explicitly designed for AR-type rifles, ensuring reliable cartridge feeding from a standard AR-type magazine, produced recoil on par with the 5.56mm Nato, and is accurate out to 800 meters (2600 ft) and beyond.

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The average hunter would be lucky to draw a tag for a white-tailed deer every couple of years, but an opportunity to hunt a mule deer, pronghorn, Elk, or even a problem Coyote or a feral hog may present itself.

Opportunities arise when you least expect them, so you don’t want to be under gunned when they do. Most hunters enjoy plinking with their rifles in the off-season or may even use their rifles for informal target shooting at the local gun club.

As such, you don’t want a caliber that’ll bankrupt you whenever you’re out shooting on the range, nor do you want a caliber that’s downright uncomfortable or painful to shoot from an AR-type platform. The 6.5mm Grendel’s recoil is on par with a .223 Rem.

The 6.5 Grendel cartridge is not only a smart-looking cartridge, with its short squat case holding the long bullet head, but it’s also ideally suited for the recreational hunter’s needs. Its long-range accuracy makes it a reliable hunting caliber for the elusive long-range plains game species.

65g 26mag B What Is The Best AR-15 Caliber Round Hunting

Vital Statistics For The 6.5 Grendel Cartridge:

The 6.5mm Grendel is an economical cartridge to shoot, priced closely to the .223 Remington cartridge, which is excellent for target practice and regular shooting.

For hunting, always use the best-constructed bullet that you can afford to ensure maximum penetration through bone to reach the animal’s vital organs reliably. “An expensive bullet remains the cheapest part of the hunt.”

The 6.5mm Grendel isn’t as fast as many magnum calibers, which makes it great. Straight-line penetration is synonymous with 6.5’s bullet design, and the 6.5 Grendel is n exception.

Whether hunting quarry at close range or surprising a coyote hundreds of meters away, the AR 15-type rifle chambered for the 6.5 Grendel cartridge will make your day!

65G 144 123 129 120 90 What Is The Best AR-15 Caliber Round Hunting

Best AR 15 Caliber For Deer Hunting

The white-tailed deer is the most popular hunting species by far due to its wide distribution and good meat yield. North America has six official species of deer, White-Tailed Deer, Mule Deer, Caribou, Brocket Deer, and Elk. For this AR-15 caliber choice, we’ll focus on the Whitetail deer.

ar 15 for hunting

White-tailed deer bucks can grow up to 300lb (136kg) in weight, with the rare buck reaching the magical 400lb (180kg) mark, so you don’t want to under gunned.The 6mm ARC is our pic for a reliable deer cartridge. Utilizing the famous 6mm, .243″ bullet, which is well known for its high ballistic coefficient and high sectional density, and low drag, the 6mm Advanced Rifle Cartridge is a winner.

Developed by Hornady, the parent cases are the .220 Russian and 6.5mm Grendel, both of which excel in their own rights in the field. The cartridge design follows the same winning recipe of the 6.5mm Grendel using a short stubby case, allowing for reliable feeding in the AR-type magazines.

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The 6mm ARC is an improvement over many of the standard bolt actioned higher velocity 6mm cartridges for hunting deer as most deer are hunted at closer distances making extreme velocity cartridges unnecessary.

The 6mm APC is no slouch, launching a 103 to 115-grain bullet at 2700 to 2800 fps from a 23″ barrel and around 2600 fps out of an 18″ AR 15 barrel. The velocity is perfectly adequate for shots on deer in the 300-to-400-yard (274 to 365m) range with the correct holdover.

At closer ranges, the massive tissue (meat) damage associated with high-velocity cartridges is largely avoided, which is excellent news if you don’t like sharing your precious venison with your canine companion.

The ten percent ballistic gel penetration test revealed that the 103-grain Hornady ELD-X hunting load penetrated 18 inches (45cm). Using heavier 115-grain heads will ensure even better penetration.

The penetration is sufficient to reach the vitals of any whitetail vital organs when taking a side on, frontal, or shots at reasonable angles reliably.

Vital Statistics For The 6mm (.243″) ARC Cartridge:

6mm Advanced Rifle Cartridge 6mm ARC What Is The Best AR-15 Caliber Round Hunting

The recoil generated by the 6mm ARC is on par with that of a .223 Rem, so it is ideally suited for use by lighter-framed hunters or recoil-sensitive hunters.

Best AR-15 Caliber For Elk Hunting

The North American Elk, or Wapiti, is amongst the most recognizable deer species. Their regal appearance and magnificent antlers make them one of the most desirable species to hunt for all trophy hunters.

Their distinctive calls can get any hunter’s excitement levels up there.Elk fit squarely into the big game deer category, with bulls weighing up to 1100 lbs. (498kg) and cows up to 600 lbs. (272kg).

When hunting big game like elk in wooded areas, a heavy large caliber bullet penetrating deeply and leaving a decent blood trail to follow is needed. Long-distance sniping at elk over 300 yards requires a high-velocity cartridge firing a bullet or 180 gr or more to ensure ethical kills.

The AR15 platform caliber choices are limited by the length of the box magazine, which accommodates ammunition to a maximum length of 2.26″. Most higher velocity cartridges, such as the .308 Win, are longer and thus unusable in AR-15-style rifles.

Fortunately, ammunition and rifle manufacturers have crossed this bridge and come up with a few AR-15-friendly big-bore cartridges, such as the .450 Bushmaster, .458 SOCOM, and .50 Beowulf, all true large-bore offerings.

The .450 Bushmaster is our choice for Elk hunting at ranges up to 300 yards (275m) which is its practical limit in terms of bullet drop. The .450 was developed as a cartridge capable of one-shot kills on big game at 250 yards (228m).

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Hunting bullet head weights offered in the .450 range from 158 gr (10.2g) to 300 gr (19.4g). The 250gr option (16.1g) provides the best compromise between penetration and bullet drop. At under 100 yards (91m), a properly placed 250 gr bullet will quickly take down the largest Elk.

The cartridge’s recoil is on par with that of a 30-06 rifle, which, although not light recoil, is manageable thanks to the vast stock options offered in the AR-15 platforms.

Vital Statistics Of The .450 Bushmaster Cartridge:

Searching the internet will reveal an abundance of accounts where bison, bears, and buffalo have been hunted using the excellent .450 Bushmaster caliber.

Best AR-15 Caliber For Hog Hunting

person taking photo of brown boar

The feral hogs are prolific breeders, and their ranges are ever-increasing. Hogs are abundant in the southern States, with Texas housing the largest population of an estimated 2.5 to 2.6 million feral hogs. With such large numbers, the hogs cause billions of dollars worth of crop damage annually.

The hog’s tenacity and adaptability are legendary, and as such, one Legend deserves another, to be precise, the .350 Legend, chambered for the AR-15-type rifle.

The .350 Legend, introduced in 2019 by Winchester Ammunition, is a newly designed straight-walled case made specifically for use in AR-15 type rifles and to circumvent the restrictions on hunting with bel-shaped cartridges in many states.

Feral hogs have muscular, solid bodies, with adults commonly weighing between 100 and 400 lbs. and more. The .350 Legend cartridge is an excellent close-range (up to 250 yards, 228m) caliber capable of felling the most giant hogs with good shot placement.

Penetration using premium bullets such as the excellent monolithic bullet heads in the 180-grain weight class, traveling at 2100 fps (640ms) and delivering 1762 ft-lb of energy will ensure roughly 19 inches (48cm) of penetration.

Being a straight-walled case and using a .357-inch (9.06mm) diameter bullet makes reloading for handloaders a simple task. Individual cartridge components are readily available, with an ever-increasing option of bullets becoming available as the cartridge’s popularity increases.

Recoil generated by the .350 cartridge is in the .243 rem category allowing fast follow-up shots if needed and making the cartridge perfect for recoil-shy persons.

Hogs are generally shot at close range, especially at night. As such, the .350 Legend is ideally suited for the task. Its heavy bullet ensures excellent penetration from the most reasonable angles providing humane kills on hogs.


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Ethan Smith is a seasoned marine veteran, professional blogger, witty and edgy writer, and an avid hunter. He spent a great deal of his childhood years around the Apache-Sitgreaves National Forest in Arizona. Watching active hunters practise their craft initiated him into the world of hunting and rubrics of outdoor life. He also honed his writing skills by sharing his outdoor experiences with fellow schoolmates through their high school’s magazine. Further along the way, the US Marine Corps got wind of his excellent combination of skills and sought to put them into good use by employing him as a combat correspondent. He now shares his income from this prestigious job with his wife and one kid. Read more >>