Building an AR-15 for hunting is an interesting project. The AR has some distinct advantages and disadvantages for hunting use and a rifle builder needs to take into consideration the specific type of hunting and climate the rifle will be used in. With the proliferation of AR-15 style rifles and a large number of people returning from the military with a good familiarity with them, the AR-15 is here to stay, both as a competition/defense weapon and as a hunting tool.
The 5.56/223 Remington
The 5.56×45 or 223 Remington was developed from the 222 Remington Magnum cartridge which was submitted to the government for review as a new military cartridge to replace the 308 or 7.62×51 NATO round. It was designed to allow soldiers to carry more ammunition and be cheaper to produce. These things don’t necessarily add up to a good hunting cartridge. The 223 can be considered a bit marginal as a hunting cartridge on big game such as whitetail deer. If the right bullets are used by a competent shooter and hunter, it can be very effective. The 223 is very effective for varmint hunting and on the smaller game animals. Laws vary state to state and need to be examined to determine the legality of using a 223 or a semi-automatic rifle for hunting.
Lighter weight bullets from 40 to 60 grains work well on varmints and smaller game animals. Larger game should be harvested with heavier, properly constructed bullets. Shot placement is critical on larger game and the 223 should only be used on large game by a calm, competent hunter that has the patience to wait for the right shot.
Barrel FactorsBarrel length can be an important consideration when building a hunting AR. The shorter the barrel, the handier the rifle can be. This is important when hunting fast moving game in heavy cover, like feral hogs in mesquite brush. Longer barrels deliver better ballistic efficiency for the most energy delivered at long range. This can be important when shooting varmints at distances past a quarter mile.
Barrel twist rate is also important. If the hunter wants to use long, heavy bullets, the barrel needs to have a faster rifling twist to properly stabilize the bullet. A 1 turn in 9” twist rate is a nice compromise and will allow shooters to use up to about a 75 grain bullet. Depending on the length of the bullet, 75 to 80+ grain weights may need a 1 in 7 or 8 inch twist to properly stabilize. If shooters are only going to use lighter bullets for closer range varminting, a 1 in 12” twist rate will work with most bullets up to 55 grains or so. The bullet weight is not the determining factor in deciding on twist rates, it is actually the bullet length.
AR-15 barrels are available in a number of different profiles. A thick, heavy barrel is great for accuracy and resisting heat buildup from long periods of firing, but the extra weight can really make the gun awkward to carry. If the rifle is only used for shooting long range varmints from a rest or bipod, the weight may be fine. If the rifle needs to be carried long distances or used quickly, a shorter, lighter barrel may be a better choice.
Hunting can occur in a wide variety of environmental conditions. From hot and dusty to snow and extreme cold, the AR can be modified to perform well. In cold environments, the aluminum parts of an AR-15 quickly become very uncomfortable to handle. The whole rifle acts like a heat sink and sucks the heat from your hands. Excess lubricant can also thicken and cause problems at low temperatures. Winter lubrication procedures and products should be used and some thought given to protecting the body from contact with the aluminum parts. White Vet Wrap used for snow camo and skin protection works well. Also wrapping aluminum handguards with a paracord whipping works excellently for protecting hands and reducing noise from things hitting an aluminum handguard, which can ring like a bell.
Keeping the rifle internals clean and lubricated is very important in hot climates. The rifle should be protected from dust as much as possible. Using the ejection port dust cover can help from keeping dust from migrating into the action.
A high quality lower receiver unit, matched upper receiver, barrel, stock and ammunition all work together to allow a shooter to maximize their hunting potential. Brigade Manufacturing Inc. manufactures a high accuracy US made AR-15 Lower Receiver machined from billet aluminum and Cerakote finished. Photos, specs and ordering information are available at www.Brigadefirearms.com or call us for more information at 855-445-9662