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 gunmaker. 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:
Recommended AR-15 resources:
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