AR-enamored deer hunters get short shrift. On one end of the stick, standard AR-15 platforms can’t house truly versatile deer cartridges. On the other, AR-10-style rifles capable of housing .308-size rounds tend to handle like railroad ties.

Blend the best characteristics of both, and you’ve got a proper deer ­rifle—​one that’s light and handy, yet powerful enough to offer flat shooting at longer ranges. It’s actually easier to do than you think. Because the AR platform is basically a big boy’s ultimate Erector Set, you can build a custom black rifle for deer hunting in your garage—and maybe even save a few bucks. That’s exactly what I did, and the result is the rifle pictured above.

Receiver: Superlight, skeletonized 2A Armament Xanthos
Trigger: ­Skeletonized Timney AR-10 Competition
Caliber: 6.5 Creedmoor
Scope: Leupold VX-6HD 3–18x44mm
Handguard: Free-floating, 9.9-ounce, 2A Armament 15-inch Xanthos
Barrel: Proof Research 22-inch carbon-​fiber-​wrapped CamGas, threaded for a suppressor

Going Hot

You can’t begin to build your own AR without first deciding what caliber you want, and when you live in the West, like I do, you want one with legitimate reach. That pretty much rules out AR-15 calibers. But several potent deer rounds shine in AR-10s, including .338 Federal, .260 Remington, 6.5 Creedmoor, and .308 Winchester.

I went with the hottest caliber on the planet right now—not because it’s trendy but because the 6.5 is inherently accurate and provides a significant ballistic advantage at longer ranges. If you don’t need that performance edge for your style of deer hunting, it’s much simpler to stick with the .308, because the Creedmoor (as well as the .260 Rem.) produces excessive bore pressure in standard-length AR gas systems. In my case, the barrel I wanted (more on that in a bit) provided a solution to the gas problem, which made choosing the 6.5 easy.

Weight-Loss Program

Starting with an AR-10 platform meant that the tricky part was getting the weight down without compromising performance. Some of the heaviest components happen to be some of the most critical for reliability and accuracy. So you can’t hack ounces randomly. A lightweight bolt-carrier group (BCG), for example, would have saved me 3⁄4 pound but would also have introduced potential tuning and reliability issues. Instead, I trimmed weight in the receiver and barrel.

Rigid design and precise machining are vital to accuracy in an AR receiver, but weight is not. As long as it’s strong and offers a precise fit with the barrel, even a superlight, skeletonized receiver can be reliable and accurate. The 2A Armament Xanthos receiver I chose is a perfect example, and it weighs just 16 ounces, compared with the 28 to 34 ounces of a typical forged AR-10 receiver set. At $949, the cost is significantly more than that of a standard receiver, but it’s worth it.

Lightweight barrels, in contrast, are inherently problematic. Machining away material reduces rigidity, allowing accuracy-killing vibration and oscillation. With less mass to absorb heat, lightweight barrels also get hot and lose accuracy quickly during longer shot strings.

There's only one good solution—and that is to get your barrel from Proof Research. The Montana-based aerospace company builds specialty tubes that provide heavy-barrel accuracy at mountain-rifle weight by wrapping cut-rifled, hand-lapped, match-grade cores with a carbon fiber that adds tremendous stiffness—around 10 times that of a similar-weight all-steel barrel. The result is superb accuracy and hot-barrel integrity in a featherweight barrel. And there's a bonus: Proof's new Caliber Matched Gas System (CamGas), which features extended gas ports in its 6.5 and .260 barrels, solves the problem of excessive bore pressure, providing reliable function and reduced felt recoil.

Instead of a fad-following short barrel, I went with a 22-inch CamGas tube, threaded for a suppressor. Even so, it weighs only 2 pounds 14 ounces. You can argue that deer can’t tell a 100-fps difference, but when a Wyoming wind stands to reroute your bullet from the vitals and to the guts, that extra speed helps to keep it on line for a clean kill.

Furniture Shopping

Because a free-floating handguard lets an accurate barrel do its work without interference, I went with a 9.9-ounce 2A Armament 15-inch Xanthos model, which is both rigid and light. I'm a trigger snob, so I installed the skeletonized version of Timney's outstanding AR-10 Competition trigger, which is as crisp as my British mother-in-law and far easier to manipulate. To make the rifle ­suppressor-​tunable, I opted for a Superlative Arms adjustable gas block rather than a less expensive fixed block.

Finally, I installed a Magpul MOE fixed stock, Hogue rubber grip, CMMG lower receiver kit, Heavy Buffer Anti-Tilt buffer and spring, and Bravo Gunfighter charging handle, most of which I ordered from Brownells (see sidebar). Having seen Murphy’s Law savage more than one scope during wilderness hunts, I also installed a set of Magpul’s folding MBUS Pro backup sights. The whole thing cost me a little more than $3,000, which isn’t cheap, but it isn’t expensive, either, for a custom AR.

Range Results

I topped the rifle with Leupold's new VX-6HD 3–18x44mm, which in my mind is the lightest truly capable long-range riflescope on the market. The finished rifle has a nice between-the-hands balance and it shoulders and points well. Not like an English shotgun, mind you, but better than many of today's modern bolt-action deer rifles, and that's saying something for an AR-10.

In the end, polite recoil, perfect reliability, and stellar accuracy makes even this black, bony-looking deer rifle lovable. Six factory 6.5 Creedmoor loads and six handloads all averaged sub-MOA groups. In a series of three groups of three shots—without cooling the barrel in between—Hornady’s 143-grain ELD-X Precision Hunter factory load averaged 0.47 inch. My Sierra 140-grain GameKing handload averaged 0.30 inch.

Granddad’s Savage 99 lever may have more charm. But my homebuilt AR is impervious to moisture and temperature extremes and is more accurate than most bolt actions. Weighing in at just 7.5 pounds and packing plenty of wallop for big whitetails and muleys way out there, it’s what you’ll never find on the rack: the ultimate deer AR.

Tip of the Month: Builder's Helper

If you're even a little bit mechanical, you can probably build your own AR, but don't go it alone. Along with many of the basic parts you'll need for your rifle, has a "Learn" section that provides a series of two-­minute videos that will make the process much easier. In addition to common household tools, you'll need a couple of inexpensive specialty tools, also available from Brownells, including a buttstock tool, a lower-receiver vise block, and a barrel extension torque tool. While common AR‑15 parts are easy to work because specs are standardized, AR‑10 parts often are not. Consult the manufacturer or supplier to be sure that the parts you want will all play nicely together. That done, assembly can be completed in an evening.