Ditch the Same Ol’ AR-15 with a BRN-180 (Lower Full Review)

Stocking up on AR-15’s ain’t a bad idea these days. Between the pandemic, social unrest, and a Democratic White House, the future looks just a little brighter with a small arsenal of effective self-defense weapons. And judging by the selection at my local gun store, I’m not the only one who’s concerned.

But even though AR-15’s are infinitely customizable and super fun to shoot, the platform can get old after four or five builds. That’s why I was stoked to get my hands on a BRN-180 upper from Brownells and even more stoked when they (finally) released the lower early in 2020.

The BRN-180 revives Eugene Stoner and Arthur Miller’s original AR-18 rifle designed in 1963. The self-contained recoil system allows the action to cycle without a buffer spring, the piston-operated design is ultra-reliable, and the handguard can be removed without tools. I published a full review of the upper in November of last year, but Brownells recently made my rifle complete by sending the lower as well.

The folding stock reduces overall length by about nine inches.

With a folding stock from Black Collar Arms, my BRN-180 is finally set up as it was meant to be, and it’s become one of my favorite rifles to take to the range.

The Lower

Brownells offers a BRN-180 lower receiver in two varieties – the BRN-180 stripped receiver and the BRN-180M receiver. Brownells sent me the BRN-180M for this review, and it’s designed to look more like an AR-15 receiver than its counterpart. It’s constructed from billet 7075 T-6 aluminum and protected with a hard-anodized finish. The mag well and trigger guard are shaped like a typical AR-15 lower, though it still features the Picatinny rail for the addition of a folding stock.

The BRN-180M receiver is solid, well-built, and features a built-in rear Picatinny rail for mounting stocks.

The BRN-180 receiver is shaped more like an original AR-18. The original AR-18 used a stamped receiver rather than the forged or billet receivers we’re used to seeing these days. But while the BRN-180 keeps the lines and weld marks of the original, it’s more durable thanks to its forged 7075 aluminum construction and anodized finish.

The BRN-180M receiver (right, used for testing) looks more like a standard AR-15 receiver. The standard BRN-180 receiver (left) more closely matches the original AR-18.

Both lowers take a standard AR-15 lower parts kit and feed from standard AR-15 magazines. Neither will work with a standard AR-15 upper because they aren’t designed to accept a buffer tube, though the BRN-180 upper can be installed on a standard AR-15 lower.

The BRN-180M can be had (when in stock) for $149.99 while the BRN-180 comes in at $129.99.

The BRN-180 is tons of fun to shoot.

The Build

The internal parts and pistol grip on my build are run-of-the-mill components from Brownells and Magpul. Brownells sent me one of their lower parts kits ($41.99), and I found a GI trigger in my spare parts bin. The pistol grip is a Mission Adaptable (MIAD) modular grip system from Magpul, which usually runs for about $35.

There’s nothing better than assembling all the parts for a new AR-type rifle.

I only had trouble with one step of the parts kit installation. Because the receiver doesn’t need a buffer tube, the rear takedown pivot spring and detent are installed in the bottom of the receiver rather than the back and are held in place with a small set screw. This process involves the usual frustrations of any takedown spring/detent install, but I found that a standard spring is actually too long for the available space. Once I cut about 0.30” from the spring, it fit perfectly, and I haven’t experienced any issues with the gun’s takedown functionality.

I had to cut the rear takedown spring to allow it to fit in the hole along with the detent. You may not have the same issue, but if you do, cutting the spring works fine.

You can jazz up your trigger and parts kit however you’d like, but the BRN-180’s best feature is its ability to accept a folding stock. The gun’s self-contained recoil system doesn’t need a buffer tube, so users can attach any Picatinny-mounted folding stock system they prefer. The most popular are the Sig MCX or MPX lines, but I went with a new Stock Option from Texas-based Black Collar Arms.

I love the skeletonized, simplified design of BCA’s stock system. The cheek riser can be adjusted both vertically and horizontally, the rubberized recoil pad provides just enough cushion for the relatively light 5.56 NATO recoil, and the stock includes QD mount holes. Plus, the 7075-T651 aluminum design is rugged but lightweight – at only 10.6 ounces, the Stock Option is a great addition to any BRN-180 build.

If you’re in the market for a folding stock, the new Stock Option from Black Collar Arms is a great option paired with a hinge from Sig Sauer.

Black Collar Arms has plans to introduce a folding hinge, but for now, I’m using a hinge from Sig. It works great, and if you can find one in stock, I’d definitely recommend it. It can be folded with one hand by lifting up on the stock, and unfolding is a simple matter of pulling the stock back while keeping one hand on the pistol grip.

The Range

If you’re curious to see an accuracy test of the BRN-180, check out my full review of the 16-inch BRN-180 upper. (Sparknotes: I found accuracy to be acceptable, but nothing to write home about.) For this review, I’m sticking to the function of the lower.

Nothing better than a sunny day at the range.

All internal components functioned properly. Trigger, selector, mag release, bolt release, and safety selector all function exactly like an AR-15, so there isn’t a learning curve if you’re already used to the standard configuration.

The only real difference in my build is the non-adjustable folding stock. I generally prefer the classic six-position stock because it allows me to tailor the length of pull to shooting position. Especially when using a magnified optic with a small eye box (i.e., the distance your eye should be from the scope for maximum field of view), adjusting the length of pull for prone vs. kneeling vs. standing allows for a quick and reliable target acquisition.

But the fixed folding stock from Black Collar Arms comes with its own set of advantages. The cheekpiece can be adjusted vertically to line up with the optic, but also horizontally to mimic some of the benefits of an adjustable stock.

And, of course, it folds! With the 16-inch barreled upper, the overall length drops from 35 inches with the stock unfolded to 26 inches with the stock folded. Plus, unlike AR-15’s fitted with folding stocks, the action of the BRN-180 allows it to be fired with the stock folded or unfolded. I’m not sure when this would be necessary—it’s hard to imagine a situation that would call for the use of a rifle but wouldn’t allow for the half-second needed to unfold the stock. But it’s cool, nonetheless.

To take full advantage of the folding stock, go with the BRN-180S. If you don’t want to deal with an SBR/pistol brace, the OAL still drops down to 26 inches with the 16-inch barrel.

You might point out that 26 inches is still too long to fit in the kind of day pack most folks might use for everyday carry. I tried stuffing my BRN-180 in a few backpacks without much success. To truly take advantage of the BRN-180’s functionality, the BRN-180S is the way to go. The 180S features a 10.5” barrel, which reduces overall length all the way down to just over 20 inches with the stock folded.

Of course, you’ll need to either apply for a tax stamp to make the firearm a short-barreled rifle or roll the dice with the ATF and get a pistol brace. Given the ATF’s stance toward gun owners lately and the confusion surrounding pistol braces, I’d bite the bullet and go with the SBR.

Legal issues aside, the complete BRN-180 is a blast to shoot. At 7.5 pounds, it isn’t the lightest AR-type rifle, but it’s still light enough to be easily maneuverable in any shooting position. I mounted a Primary Arms 2x prism scope, which I’ve found to be just enough magnification for the short-to-mid range work I’ve been doing with this rifle.

Last Shot

The complete BRN-180 ain’t cheap ($130-150 for the lower + $900 for the upper + parts), but it’s a great option if you’re in an AR-15 rut. The side charging handle and folding stock are eye-catchers at the range, and the rifle is reliable and accurate. While your buddies are building another AR-15 for their ever-expanding collection, branch out to something a little different and check out the BRN-180 from Brownells.

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About the author: Jordan Michaels has been reviewing firearm-related products for over four years and enjoying them for much longer. With family in Canada, he’s seen first hand how quickly the right to self-defense can be stripped from law-abiding citizens. He escaped that statist paradise at a young age, married a sixth-generation Texan, and currently lives in Waco. Follow him on Instagram @bornforgoodluck and email him at jordan@gunsamerica.com.

{ 3 comments… add one }
  • Tom January 18, 2021, 2:24 pm

    Are the powers full ambi? If not, they need to be

  • JohnL January 18, 2021, 8:16 am

    I have a Gen1. It pisses me off that they immediately came out with an adjustable gas block one? They also sent me to PWS for questions and PWS does not call back. The system itself is a good one! I like it, A bit heavy so I used a poly lower (http://www.tnarmsco.com/). It s nice. I would stay away from long LOP stocks. I find due to weight distribution it needs to be closer to my body. I like Brownells so that is why I am complaining about roll out and CS!

  • VirtualWatts January 18, 2021, 6:58 am

    I have the 180s on a lower with folding pistol brace (SB3), did that while getting it SBR’d and the package is so tight just left it. with suppressor still a tight kit and handy to fire folded.

    My upper failed at 4k rounds due to some engineering issues in the bolt carrier and recoil springs.
    There are some good and bad with the setup. I have already had to replace the upper once due to catastrophic failure on the rails. PWS replaced it and the replacement was a bit beefier. Unsuppressed works like a rock star, but suppressed the twin buffer springs are too light and the gas has no adjustment beyond “suppressed”, it is overgassed/under spring’d and the bolt carrier slams to the rear of the upper receiver (no buffer tube remember?) causing the bolt to rotate violently in the carrier and slam the bolt cam into the rails in the upper receiver. The replacement had beefier bolt spring and rails appear slightly different but didn’t mic them.

    This exact problem exists on the Browning BAR when suppressed, which has a similar gas/rail arrangement.

    Don’t get me wrong, love this thing for small package, very accurate, nicely designed. But wouldn’t want it to be called out to be reliable without adjustable gas block or beefier bcg buffer springs.

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