Brownells 75th Anniversary - A Shooting Heritage
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Carte Blanche Build

By Iain Harrison

Photos by Straight 8

If one were to list the reasons for building a top-shelf AR, "Because I can," would fall pretty near the top. So using that philosophy, we did just that. By Iain Harrison Photos By Straight 8

Look, we get it. Not everyone has the scratch to put together a build like this, and just about all of us can come up with more pressing applications for seven G’s. But sometimes you just gotta go with the premium product. After years of building rifles for competition, hunting, training, and self-defense, there comes a time in a man’s life when all those times you decided to substitute the cheaper component, or delayed gratification in order to wait for a special offer, eventually pay off. This is our dream rifle, and this is why we chose the components we did.

The AR-15 started out as a lithe, stripped-down carbine and slowly, like a faded, middle-aged action movie star, succumbed to the vicissitudes of a Vegas buffet diet. The AR porked out. At the end of the last century, it seemed the prevailing mindset was that naked rails were a very bad thing, so all sorts of crap needed to be bolted on in order to maintain the gun’s modesty. Sixteen inch government-profile barrels became all the rage, despite being the most idiotic shape ever devised — if anti-gun politicians sought to ban rifles based on looks, we can only surmise that the public bought them for the same reason. Fortunately, the wheel of fashion turns and the AR is slowly getting back to its roots, so we decided to see if all of the additional functionality and refinements of the last 20 years could be squeezed into a carbine that weighed about the same as the original.

Our build started with a matched set of receivers from Battle Arms Development. Milled from 7075 aluminum bar stock and heat treated to a T6 temper, they’re plenty strong and have had every bit of excess fat trimmed away. Additional time on a CNC machine means they’re not cheap, but they manage to shave a couple of ounces from the overall total and the only way to get to our weight limit is by an ounce here and a gram there.

Two more ounces are saved through the use of a Rubber City Armory lightweight bolt carrier group, but perhaps more importantly, the carbine’s recoil impulse is softened, as there’s less disturbance as the bolt slams home. RCA employs salt bath nitriding as a means of surface hardening both bolt and carrier, which increases lubricity and corrosion resistance to levels above that of hard chrome.

One of the most critical components of any build is the barrel, and it’s also the place where the biggest weight savings are possible. In past builds we’ve used pencil profile tubes when the rifle is designed to be carried much and shot little, but their lack of thermal mass means that they heat up very rapidly when shot, which more often than not leads to a degradation in accuracy. Given the high quality of this build, we wanted to be able to get solid, 600-meter head shots after dumping a mag into close range targets, so a lightweight profile barrel might be good for hitting our weight goal, but wouldn’t be much good for hitting anything else.

Proof Research has developed a solid reputation when it comes to producing consistently accurate, lightweight barrels through the use of a carbon-fiber wrapping process. In it, a conventional, match-grade stainless steel barrel is turned down to subpencil diameter, then carbon-fiber filaments are wound around it, stiffening it and improving its thermal transfer properties. The result is a lightweight barrel that performs like a heavyweight — perfect for this rifle. As we’d already decided on using a Gemtech ONE suppressor for this project, an adjustable gas block was added to the parts list in order to manage gas flow and reduce the amount of propellant coming back at us.

There’s not much point in creating an intrinsically accurate rifle if the human directing it can’t utilize that accuracy. Stuffing a gritty, 7-pound GI trigger in a high-end carbine is like wearing old work boots with a bespoke suit — there’s a time and place for both, and this ain’t it. Two-stage triggers are favored for long-range work, while single-stage units are at home while hammering close range targets. The AR Gold drop-in unit spans both of these applications as it’s a two stage with a very short, light first stage and an even shorter reset, so given its jack-of-all-trades demeanor, we added it to the spec sheet.

The next set of components had us struggling to justify the increased weight, but the additional utility offered by the LAW Tactical folding stock mechanism ultimately won out. Teaming it with a Battle Arms Development Sabertube allowed us to eliminate a conventional stock and save a couple of ounces there, while the folder enables the carbine to fit inside a backpack, without having to be disassembled.

In order to bridge the gap between bolt carrier and buffer created by the folding stock mechanism’s additional length, LAW employs a steel plug which sticks out of the carrier’s rear end. This adds a little mass to the reciprocating parts, so in order to maintain our anorexic program, we gutted the sliding weights from buffer. These typically act to counteract bolt carrier bounce in full-auto fire, but as this build is strictly semi-auto, we felt no remorse in taking them out. Returning the working parts to battery was handled by a JP tuned recoil spring, which, thanks to being ground and polished is smoother than a conventional music wire spring.

We’d initially ordered a Seekins NOXS 12-inch handguard to cover our carbon fiber barrel. While lightweight, contoured and sexy, the BAD receivers were also very picky regarding the forend they’d accept. Several options were tried and each presented the same problem, namely a 1/8-inch wide gap at the top rail. After much trial and error, a Bravo Company KMR Alpha 13-inch rail was settled upon. While we could have knocked 2 ounces off the total weight by going with the magnesium alloy version, it seemed like everyone else in AR-land had come to the same conclusion.

At the sharp end, the finishing touch was provided by a Gemtech Quickmount, which interfaces with their cans to permit removal after heavy doses of sustained fire. Although it’s strictly a flash hider with no recoil reducing properties, the combination of a tuned gas system and reduced reciprocating mass left one of our test shooters thinking that he was laying down rounds with a brakeequipped carbine.

So was the goal achieved? Yes and no. While the carbine we built tipped the scales at a rather appealing 6 pounds, 2 ounces, we completely blew the budget when it came to the optic. Figuring that you only live once, we picked the most bad ass, versatile carbine scope in existence. The only downside to the magnificent Leupold Mk 8 (apart from its stratospheric price tag) is its weight. True, it feels like you could use it as a pry bar or to subdue unruly bar patrons, but the downside to its robust construction is that it feels like you’re zip tying a brick to the upper receiver. Still, we’d saved so much weight in other areas that we felt justified in adding it to the carbine. At least, that’s what we kept telling ourselves.

One of the great appealing features of the AR-15 as a platform is the nearly infinite number of component variations. We don’t claim to have put together the ultimate AR, but this one’s a rifle that blows up our skirt when it comes to quality components. No doubt you’ll have your own opinions regarding the parts we picked, but that’s the great thing about this nation and free enterprise — you’re entirely at liberty to pick whatever you want to scratch the rifle building itch, and there are a huge number of companies out there to help you do it.