Modern hunters want modern guns, and the light-hitting .223 isn’t the only caliber offering for tactical rifles. The first decision you’ll have to make is what size AR you want. There are two sizes to choose from, with the most popular being the AR-15 our military uses. Then there is the larger original size most commonly referred to as the AR-10— which is most commonly chambered in .308 Winchester.
By Robb Manning
Whether you choose the standard or larger size will determine what calibers you’ll have available. The larger sized AR provides options in the high-power cartridge range, such as the .308 Win. The standard sized AR has fewer whitetail cartridge options, but its smaller, lighter size is better suited for hunting in tree stands and confined spaces such as deer blinds, and is easier to carry.
Whitetail hunting for me is spent in a tiny hang-on tree stand or sitting in a tripod blind. The best choice for these confined spaces is the standard AR-sized rifle.
The small receiver with carbine length barrel and collapsible stock are tough to beat when maneuverability is important. Following are two deer-suitable calibers growing rapidly in popularity for these smaller rifles. Note that I limited the choices to those most easily found on the shelves of local stores.
I’m a huge advocate of the 6.8 SPC (Special Purpose Cartridge). It’s my favorite AR cartridge.
A lot of shooters agree, with it being the second-best selling AR cartridge on the market right now, and it’s not because of a big corporate push but rather the people who shoot it and hunt with it. Thankfully, more ammunition manufacturers are jumping on the 6.8 SPC wagon, making it more common on store shelves and online.
Offerings range from good-quality budget ammo from Sellier & Ballot and American Eagle to high-end custom loads from Wilson Combat. Silver State Armory makes excellent ammo at a great price, as does Federal Ammunition.
Having a giant like Federal behind the cartridge makes it a sure bet you’ll be seeing more of it. Additionally, in 2013 Federal released the Fusion MSR 6.8, ammunition specifically designed for hunting with 6.8 SPC ARs.
Of all the AR deer cartridges on the market, the 6.8 SPC is the most versatile, and I believe it’s the best. It’s perfect for whitetail, great for hogs and it doubles as a fantastic defensive round. The .270-caliber bullet shoots flat and retains its energy well down range. A 95-grain bullet leaves the barrel at 2,850 feet per second and has 1,715 foot-pounds of energy. A 110-grain bullet flies at 2,700 fps with 1,780 ft.-lbs. of energy.
Hot on the heels of the 6.8 SPC in popularity is the .300 BLK (AAC Blackout). But I have to confess, I’m not on the bandwagon here.
Still, it’s very popular and has a growing fan base of hunters. The primary advantage to the .300 BLK is that it is available in subsonic rounds in stores. However, subsonic performance on whitetails negates this advantage. I talked to Chris Lucci, owner/operator of the Wild River Ranch in Texas, about the .300 BLK. Chris tests this stuff, using it in the real world, and between him, his staff and his clients, a lot of whitetail and hogs are killed at WIld River.
Hunting subsonic with the .300 BLK is, as far as ballistics are concerned, like hunting with a 9mm MP5, and the deer don’t always go down like they should. A suppressed 220-grain bullet has a velocity of 1,020 fps and 508 ft.-lbs. of energy.
A supersonic, nonsuppressed, 110-grain bullet has a velocity of 2,350 fps with 1,349 ft.-lbs. of energy. If opting for the .300 BLK, I would recommend staying away from the subsonic rounds. For most hunters, it simply won’t matter.
When not constrained by the tight confines of a small blind or platform, the larger sized ARs in the AR-10/SR-25 models give you a lot of excellent choices in caliber, and most weigh in at around eight to 10 pounds, so they’re still plenty light. Here are five calibers that all make excellent choices:
.308 Win.—The .308 Winchester, also known as the 7.62x51mm NATO, is one of my top two favorite cartridges of all time. An excellent all-around deer hunting cartridge, the .308 Win. was designed to replicate the ballistics of the .30-06 Springfield, but in a length that fits in a standard-length action rifle. The .308 Win. has more bullet options from more manufactures than just about any other rifle cartridge. It’s capable of excellent accuracy with excellent performance—a 150-grain bullet leaves the barrel at 2,820 fps and has 2,648 ft.-lbs. of energy, twice the energy of the .223 Rem.
7mm-08 Rem.—Much can be said about the flat-shooting 7mm (.284 caliber), and with its outstanding accuracy, it makes an excellent long-range whitetail choice. Based off a necked-down .308 Win. case, the 7mm-08 has all the virtues of the 7mm, but delivers it in the AR-10/SR-25 platform. A 140-grain soft point exits the barrel at 2,860 fps with 2,542 ft.-lbs. of energy.
.243 Win.—Developed in 1955, the .243 Win. (6mm) met immediate success and was soon chambered in the rifles of several U.S. manufacturers and almost every European gun maker. Its parent cartridge is the .308 Win., which makes it perfect for the AR-10/SR-25 platform. At the light end of bullets, its high velocity makes it an excellent choice for smaller game, and at the heavy end it’s suitable for whitetail. The 80-grain is fast at 3,550 fps and 1,993 ft.-lbs. of energy. For whitetail, the 100-grain bullet leaves the muzzle at 2,960 fps with 1945 ft.-lbs. of energy. New bullets from Barnes, Hornady and Lapua have made this an even more lethal whitetail bullet.
.260 Rem.—Another cartridge from the .308 Win. family, the .260 Rem. is a good long-range cartridge and is excellent for whitetail. It’s also a good choice for shooters who are recoil sensitive. Performance wise, the .260 Rem. far exceeds the .243 Win. and is not far behind the 7mm-08 Rem. A 140-grain bullet leaves the muzzle at 2,750 fps and has 2,351 ft.-lbs. of energy.
.338 Fed.—Following a trend, the .338 Fed. was spawned from the .308 Win. and necked up to a .338-caliber bullet. Excellent for close- to mid-range whitetail, elk and bear, it’s borderline big in areas with small-framed whitetails, but will still work. Surprisingly mild in recoil compared to other cartridges in this caliber range, a 180-grain bullet travels at 2,830 fps with 3,200 ft.-lbs. of energy.
The continued growth of the AR in the hunting field demonstrates the effectiveness of the rifle. With more makers designing them for hunters and the continued expansion in caliber choices, it’s no wonder why they’ve become so popular. With the effectiveness of these .223 alternatives, there’s little reason to use the .223, even in areas where legal.
Deer-Worthy AR Calibers:
This article appears in the November 18, 2013 issue of Gun Digest the Magazine. Click here to load up on a subscription.