The caliber of your firearm is more than the size of the bullet, it’s the reason for your firearm’s existence. Most guns are designed around cartridges, not the other way around. And many exist solely to chamber and fire a single specific cartridge. Not for the trusty AR.
While initially designed around the 5.56 NATO cartridge, the AR platform is unique in that it has been evolved to employ a wide variety of cartridges, each with specific characteristics. If you’re wondering what caliber or AR to buy, there is no one-size-fits-all. Each different cartridge available on the platform has unique characteristics, making them better or worse suited for specific applications.
Calibers vs. Cartridges
First, let’s clarify terms. Cartridge refers to the overall ammunition – case, bullet, propellant, primer – the whole pew pew. Caliber refers to the size of the bullet. The higher the number, the larger the bullet. Although the terms are often used interchangeably, caliber is just one characteristic of the cartridge. And the cartridge is what you put in the gun. (If it’s the right caliber.)
Determining which caliber of firearm is best for you depends on the type of game you’re after. Generally speaking, the larger the bullet caliber, the larger the game. If you’re using too small of a bullet caliber, you may not have the energy to take down your prey. Too large of a bullet, and you may ruin the hide or meat of what you’re shooting, not to mention wasting energy. Some hunters believe in a “less is more” approach, using a relatively low-power ammo for as big an animal as they can down with it. While others prefer “more is more,” pumping as much energy into a beast as they can bring to bear.
Whichever approach strikes your fancy, there’s no denying that some cartridge calibers are simply better suited for certain game than others. We’ll break down the different categories of game and which cartridges are best suited for which and what ammo goes along with them.
Keep in mind though, this is just a guide. Some calibers (like .450 Bushmaster) are just as effective as target shooters as they are at taking down game. And we are by no means suggesting we have all the answers. Some hunters and shooters will certainly disagree with our choices. But if you’re just starting out and wondering which caliber to buy, this article is a good place to start.
Matching Calibers to Game
Varmints and Small Game
Generally speaking, most AR calibers are too high powered for varmints or small game like squirrels and rabbits. If this is the game you’re after, you’d do better with a small caliber rifle like the .22 LR. But if you must execute the smaller game with an AR, anything bigger than a .223 or 5.56 NATO is not recommended.
For animals like coyotes or wildcats, you have a few options. .223 and 5.56 NATO are – by far – the most popular cartridges for the AR platform, and for good reason. After all, they’re what the AR platform was designed to shoot. .223 is also widely available and relatively inexpensive. You’ll have only a slightly harder time finding 5.56 NATO, but by-and-large, the two calibers are almost identical in bullet weight.
5.56 NATO can be loaded to higher pressures, which means you should avoid using 5.56 ammo in a .223 chambered rifle. Doing so could prove dangerous. Shooting .223 out of a 5.56 chambered rifle will not give you any problems, although the pressures will be reduced, leading to lower muzzle velocity. If you want the flexibility to shoot either cartridge with minimal loos of velocity, the .223 Wylde chambered rifle is designed to offer just that.
Whichever chambering you choose, either .223 or 5.56 NATO are more than adequate for taking down predators of any size.
For longer range or if you just want to pack a little extra firepower, .243 Winchester is a good choice. While potent enough for hogs (or even small deer), the .243 Winchester can offer gentle enough recoil for young people or first-time shooters, but enough power to bring down most large predators.
Don’t forget the venerable 7.62x39. This caliber made popular in the AK-47 is well-suited against predators of all sizes at medium to long range. Some deer hunters even swear by it.
We round out the mid-range predator calibers with .300 Blackout. Designed for use by the US military as a round to rival the 7.62x39, .300 Blackout performs almost identically to that round in every way, making it more than adequate for use against predators. As a side benefit, .300 Blackout is dramatically quieter that 7.62x39 and 556 NATO, making it a great choice for shooting subsonic with a suppressor. Its effective range cannot also be scoffed at.
While several of the calibers above are perfectly fine for hunting small deer, if you’re looking for a more powerful round to take on more powerful, well, deer (or elk), these calibers will give you the extra punch you’re looking for.
With the same case head size and powder capacity of the .223, the .350 Legend is an easy-shooting, straight-walled cartridge. It was specially developed to be legal in states that outlaw necked cartridges, with the added bonus of sporting larger grain bullets than .223 with enough power to take down larger game. A relatively new cartridge, .350 Legend has taken the shooting world by storm, and is currently one of the more popular AR cartridges, especially among deer and medium-sized game hunters.
If you live in a state that allows necked cartridges, chances are you’re already familiar with .308 Winchester. One of the most popular cartridges in the world, .308 has been used for decades by hunters of deer and all kinds of other game. Available on the AR-10 platform, .308 remains a venerable shooter.
For long-range performance on the smaller AR-15 platform, 6.5 Grendel is your huckleberry. Shooting a relatively flat trajectory with a high-velocity, mid-size projectile, 6.5 Grendel is as close to an all-around solid performer as exists on the AR 15 platform. It will bring down almost anything you set your sights to in the 300 yard range, which, for most hunting, is as far out as you’re likely to shoot anyway.
Large Game: Elk, Moose, Bison, Etc.
Traditionally the realm of heavy bolt-action rifles, the advent of the AR-10 platform and a handful of big-bore AR-15 cartridges have brought big game hunting to the modern sporting rifle. If hanging a large trophy on your wall is what you’re after, one of these cartridges may be what you need.
.458 SOCOM is a low-velocity, heavy grain cartridge suitable for shooting at short to medium range. Will it take down a bear? You bet. Do you want to get that close? Your call.
For something with power close to the .458 SOCOM, but in a straight-walled cartridge, look no further than .450 Bushmaster. Delivering up to a 300 grain bullet at muzzle velocities hovering at or just above 2,00 fps, the .450 Bushmaster is an immensely powerful round that’s legal in states that have outlawed bottle-necked cartridges.
The 12.7x42 is the cartridge for you if you want something akin to a .50 cal round in an AR platform rifle. Based on the ludicrously powerful .50 Action Express (think Desert Eagle), 12.7x42 mounts 300-400 grain bullets dumping between 2,330 and 2,8768 foot pounds of energy on-target. It is a slow, heavy, powerful cartridge, capable of taking down practically anything you want to mount on your wall with excessive force.
More popular with competitive long-range shooters than hunters, 6.5 Creedmoor is nevertheless a notable round here. Effective as a hunting round out to around 600 yards, Creedmoor puts serious firepower into “reach out and touch” range on the AR-10 platform. Better still, it does so with a relatively mild recoil, which will help you keep your aim true.
As we said up above, these are merely suggestions. Plenty of hunters have brought down plenty of game with plenty of calibers, and if you, too, want to try your hand at hunting everything on four legs with just one of these cartridges (or something else entirely), more power to you. But we hope this article gives you an idea of just how man cartridges are available for the AR platform, and what each was designed for. Your mileage, as always, may vary.
To help further in navigating picking out calibers we offer a beautiful infographic on picking out the best caliber for hunting with an AR-15. In this infographic we take a deeper look at game animals and the effective ranges of each caliber bullet. Leave a comment down below about your favorite animals to hunt with an AR-15 and check out some of our helpful infographics!
Hunt With the Perfect Caliber
Hunting is a very exciting and fulfilling pastime. Going deer hunting is becoming more and more popular every year.
People hunt for a variety of different reasons. These include hunting for food, animal hides, exterminating varmints that damage crops and land, or just to commune with nature. Whatever the goal, it is vital to hunt in the most humane way possible. This can be done while still experiencing the thrill and joy of the hunt. The selection of an appropriate hunting caliber can sometimes be a complex undertaking. That's why we've created this infographic to give you more information on the effective range, recoil level, and type of game that can be hunted with each caliber!
***PLEASE NOTE: Most states have very specific laws governing the calibers and even types of firearms that can be used for hunting. Federal laws also apply. For example, it is illegal to kill migratory birds, which are protected by Federal game laws, with rifles. A partial list includes doves, geese, ducks, and crows. Be sure to check with your local Wildlife Commission for hunting laws in your area. We have included links to Wildlife Commissions in most states. Here.
SELECTING A CALIBER
Sometimes distance might be your ally when hunting some dangerous prey; in these cases, choosing a caliber with effective range and great stopping power is key.In addition to matching the caliber to the game you are hunting, bullet weight and type are also important. While a light-jacketed spire point may be adequate for small game, a heavy-jacketed flat nose may be best for thick hide, muscular game such as bear. Ammunition manufacturers have recommendations to help in matching the bullet to the game.
Varmints include coyotes, prairie dogs, foxes and various rodents. Commonly known as pests, these animals are not particularly complicated to hunt as they are usually not for subsistence or hide harvesting. They are quite easy to kill and can be hunted using a wide range of calibers.
Making sure you are in range might be a difficult task due to certain terrain so another thing to consider might be the weight of your rifle. When hunting animals that live in difficult terrains, such as mountains, a lightweight rifle would be ideal.
If you have further questions or need help in figuring out what caliber would be best for your needs, check out our blog on ' The best AR calibers'. If you still have questions please contact us on social media or through our amazing customer service! Look out for more entertaining and informative blogs coming soon.