Brownells BRN-180 Barreled Upper Assembly

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Synonymous with Colt, the AR- 15/M16 was originally developed by Eugene Stoner at the Arma Lite division of Fairchild Industries. Arma Lite’s facility was located in Costa Mesa, California and it licensed the AR-15/M16 design to Colt which won the original US government contract for production of the M16, notable for its widespread use of aluminum alloy construction and incorporating the patented internal piston gas operated bolt actuation system. That story has been told ad infinitum over the past 50+ years.

But in the early 1960s, with the licensing of the AR- 15/M16, the question for Arma Lite was, "What’s next?" Led by designer Art Miller, a team at Arma Lite consisting of Eugene Stoner, Charles Dorchester, and George Sullivan then developed the AR-18, a next generation lower-cost select-fire rifle fabricated from stamped and welded steel and which employed a four-piece short stroke external piston-driven bolt actuation system very similar to that of the proven Soviet SVT rifle Top: The original Arma Lite AR-180 was lightweight, being fabricated from welded stampings, incorporating short-stroke external piston actuation, and a folding stock made possible by a bolt carrier riding on two guide rods within the upper receiver.

A proprietary version of the AR-15 magazine was used. This version kept the short-stroke external piston and bolt carrier of the original AR-180 but featured a polymer lower receiver and a non-folding stock. The AR-180B uses conventional AR-15 magazines. of WWII. Besides the stamped and welded construction and the gas piston actuation, the AR-18 was notable due to its bolt carrier being supported on two guide rods and returned to battery with are- Photo courtesy Brownells. coil spring on each guide rod.

This mechanism was contained within the upper receiver, allowing for a folding butt stock which was another primary feature of the weapon. The lightweight AR-18’s semi-auto version, the AR-180, was introduced to the civilian shooting market in 1969

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to lukewarm reception because the AR-15 had ahead start in the market and was seen on the evening news nearly every night.

Over the years, the AR-180 itself eventually developed a cult following, and design elements of the AR- 18/AR-180 were incorporated into a few self-loading military rifles around the world, including the British SA-80 and the Singaporean SAR-80 and SR-88, the Bushmaster / Remington / Magpul ACR, Because of the open area of the M-Lok hand guard and the potential for burns, it is not recommended to place one’s weak hand in this area.

The bolt is similar to that of the AR-15 but has no gas rings and features a return spring on the tail. The bolt cam pin is different from that used in the AR-15, but the firing pin is identical. and others.

The AR-180’s longerterm commercial success was also hampered by a relatively non-competitive price compared to the Colt AR-15 along with the AR-180’s use of a proprietary version of the AR- 15/M16 magazine, with a narrow magazine catch notch on the right side as opposed to the AR-15’s wide rectangular mag catch window on the left side.

Production of the AR-180 was outsourced by Arma Lite to Howa Far The 17 Design and Manufacturing 17DM-180 lower receiver incorporates a "dam" in front of the magazine release and a thoughtful recess in front of the trigger for resting one’s finger. in Japan and soon after to Sterling Armament in the UK after anti-war protests in Japan caused political pressure on Howa. Sales were sluggish, with some small countries purchasing limited quantities of the weapon. Reception by law enforcement remained weak.

It’s been claimed that the end user most associated with the AR- 180 is the Irish Republican Army, which obtained significant quantities and used them during the period known as "The Troubles" from the late 1960s to the late 1990s. Northern Ireland was and is apart of Great Britain (officially known as The United Kingdom of Great

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Britain and Northern Ireland), and the civil war there pitted Catholic against Protestant, and everyone against the British troops who were there to "keep the peace," but were largely used for target and IED bombing practice by the IRA. Not a good time. Fairchild/Arma Lite eventually closed up shop. In 1996 the rights to the name were purchased by Eagle Arms, a firearms component manufacturing enterprise that changed their name to Arma Lite and introduced a slightly upgraded version known as the AR-180B.

The most significant change was adoption of a polymer lower receiver and minor changes to the upper assembly. There was no operating handle slot cover, and an exterior bolt catch "button" or "lever" was omitted. The bolt carrier would latch to the rear on an empty magazine, and with a full magazine inserted the bolt and carrier would advance forward following a slight tug to the rear on the operating handle, much like "sling shotting" an open pistol slide.

The AR-180B barrel had an integrally-machined compensator at the business end to meet the requirements of the then-waning 1994-2004 Assault Weapons Ban. The AR-180B was introduced at serial number 200000 at a surprisingly low price point of $499 in the early 2000s. Many retailers charged MSRP or even added a premium because at the time the AWB drove high demand.

Arma Lite quickly increased their MSRP to match market pricing, but two short years later the AWB ended and the market flooded Far The pointed tips of the guide rods pass through twin holes in the front of the BRN- 180 upper receiver. This design traces back to the original AR-180 of the 1960s.

The boss at the rear of the 17DM-180 lower is mostly solid with a short length of M1913 rail machined into its rear side for stock or hinged adapter mounting. with semi-auto rifles, including the first generation of the Kel Tec SU-16, another polymer-framed 223 Remington-chambered carbine that was a couple-few hundred dollars lower than the AR-180B. Production of the AR-180B ended sometime around 2007-2009.

They still sell on the secondary market for $800 and up, lately more "up" since the Covid19 and 2020 election events. But enough history! The AR-180 design refuses to ride off into the sunset. In 2019, Brownells partnered with Primary Weapons Systems and Foxtrot Mike Products to introduce the BRN-180 upper assembly, a further-improved take on the original

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design and that of the AR-180B. Recently, Brownells released the BRN- 180 upper in a Gen 2 configuration offered in 300 Blackout or 223 Wylde, in 10" pistol and 16" carbine lengths, the latter of which is the version that this article deals with.

A customer recently brought in a 16" Gen 2 BRN-180 upper chambered in 223 Wylde, a Lage Manufacturing glass-reinforced polymer stock reminiscent of the metal folding stocks on a Para FAL or Galil, and ordered a 17 Design and Manufacturing 17DM-180 lower receiver with a short M1913 rail on the rear for mounting the stock and adapter. Some assembly was required, and that’s where I entered the picture.

This customer is one of the most intelligent people I know, has an eidetic memory, and can perform complex arithmetical operations in his head, and quickly. But he is also intelligent in realizing his limitations, because hands-on practical skills were not issued to him at the factory. It’s not much of an exaggeration to say that he wouldn’t know which end of a Crescent wrench goes on the nut.

On the other hand, I am insanely jealous of his ability to multiply three random four-digit numbers in seconds using only the brains he was born with. The customer read this and approves this message.

The BRN-180 Gen 2 upper receiver assembly features an anod- The total package weighs 6.8 pounds. ized alloy upper receiver and freefloating Midwest Industries M-Lok hand guard that is mounted by eight screws to an anodized alloy adapter block which in turn slides on the mating cylindrical chamber section of the barrel. The hand guard is held fast to the receiver by a single cone-point setscrew with a 5/16" hex recess that engages a slanted surface in the underside of the barrel.

This makes for exceptionally quick removal of the handguard for access to the gas piston system beneath. The fit between the hand guard mounting block and its mating surface on the barrel is a close one, and separation required a few taps with a cloth-covered urethane- Far Rotating the gas piston 90 degrees to vertical selects the "suppressed" position. The BRN-180 Gen 1 featured two different gas cylinders, one each for suppressed and unsuppressed operation.

All it took was layout, drilling, and tapping of two 10-32 holes, 5/8" apart.

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faced hammer. The first generation Brownells BRN-180 employed a Ushaped key for attachment of the free-floating hand guard, which was more involved for removal of hand guard, and required considerably more machining. The Gen 2 setup is a definite improvement. The bolt is enclosed in a short rectangular carrier block that rides on two guide rods each equipped with a recoil spring.

The bolt is very similar to that of an AR-15, but is of slightly different configuration in the body and does not incorporate gas seal rings because it does not need them. The firing pin appears to be dimensionally identical to that of an AR-15. The bolt carrier guide rods are molded into a polymer block that forms the rear cover of the BRN-180 receiver. The recoil guide rod/spring assembly is a friction fit in the end of the receiver and requires a good, firm grasp and tug for removal, but no tools are required.

The bolt carrier and bolt are pulled to the rear by a crank-shaped operating handle that is reminiscent of that on a child’s jack-in the-box toy. It is said to have been specifically designed with the two 90 degree bends in the original AR- 18/AR-180 for left hand access for charging or clearing the weapon as well as acting as a cartridge case deflector to prevent ejected empties from impacting on the right side of the receiver, and to keep empties out of the face of a left-hand shooter.

It may look unconventional, but it works well for both intended purposes. Still, for some reason "Pop Goes the Weasel" passes through my mind when I look at the operating handle or grasp it to manipulate the bolt carrier.

Regarding disassembly, once the recoil guide rod/spring assembly is removed, the bolt carrier assembly is removed by first pushing the operating rod towards the rear until the operating handle reaches the end of its slot in the receiver, then withdrawing the handle from the bolt carrier, and allowing the bolt carrier to fall out the rear of the receiver in a controlled manner. Once the operating bits are out from inside the upper receiver, return focus to the front of the BRN- 180 Gen 2 assembly.

After sliding the hand guard off the front of the barreled upper as previously described, the gas system is readily accessed and consists of four main parts, from front to rear: Mounted to the barrel is the gas block with integral piston, then comes the cuplike cylinder with vent holes, the operating rod link which couples the piston to the operating rod and facilitates disassembly, and the operating rod/operating rod spring assembly.

To disassemble the gas system, grasp the operating rod at its front bell-shaped end and pull the operating rod to the rear, separating the operating rod link from the cylinder’s tail. Push the operating rod to one side or the other so that the operating rod link clears the piston’s tail, withdraw the operating rod link off the front of the operating rod, and then pull the piston cup from the gas block. Pull the operating rod and its return spring forward from its the hole in the front of the upper receiver.

At the front of the gas block is what appears to be a slotted screw head which is a two-position gas selector primarily intended for firing the BRN-180 upper assembly either suppressed or unsuppressed mode. The slot in the gas selector is positioned horizontally for unsuppressed operation, and rotated vertically when a suppressor is fitted. The selector is actually the gas piston, and can be removed by pushing the slotted screw end toward the rear of the weapon.

There’s a tiny alignment tab and slot on the selector/piston body and gas block to ensure correct assembly. That’s it for disassembly, and reassembly is of course the opposite procedure. The dual recoil springs of the BRN- 180 do away with the need for a buffer tube, and the 17DM-180 receiver has a solid rear boss into which a short M1913 rail is machined for accepting a stock adapter, either folding or fixed.

The original Arma Lite AR-180 featured a folding stock, whereas the Arma Lite AR-180B had a fixed solid polymer stock. Aftermarket sources offer anodized aluminum folding and fixed stock adapters for AR-180 type rifles and others using compact spring bolt return systems. The customer elected to go with a fixed Lage Manufacturing skeleton buttstock made from glass-reinforced polymer to save weight.

The 8-1/2" pull of the stock was going to be too short without the length of an extended folding adapter, and I recommended purchase of a Lage polymer stock spacer. The customer obtained that, but online sources for a fixed stock adapter for BRN-180 style lower receivers had dried up in the spring of 2021, so the suggestion was made to go with an M1913 optic adapter and just drill and tap two 10-32 machine screw holes on the proper 5/8" centerline.

Such optic mounts are available all over Amazon and e Bay, and a search turned up a UTG Super Slim RMR mount that looked fairly symmetrical and had

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Top: The BRN-180 upper assembly and 17DM-180 lower receiver breaks open for field stripping just like the AR-15 by pushing out the rear receiver captive pin. The guide rod/recoil spring assembly is first removed from the upper, then the bolt carrier is slid to the rear so that the operating handle can be withdrawn from the carrier to the right side. It is then removed out of the rear of the upper receiver. At top, hand guard and hand guard setscrew.

Second row, operating handle, operating rod, operating rod link, gas cylinder, gas piston, and retaining clip. Third row, barreled upper receiver assembly. Fourth row, firing pin, bolt key, and firing pin retaining pin. Fifth row, bolt carrier guide rod and recoil spring assembly, bolt carrier, and bolt. Photo courtesy Brownells. sufficient thickness for tapping the two stock mount screw holes 0.625" on centerlines.

The assembled rifle and stock/spacer/adapter ended up with a comfortable and quick-toshoulder pull length of exactly 13 inches. During range testing after mating the BRN-180 upper to the assembled DM17-180 lower, 55 grain Federal XM-193 ammunition was fired with the gas selector in unsuppressed mode and there were no failures to feed, extract, or eject in 180 rounds. Some might say that was an expensive test considering Spring 2021 ammo prices, but that XM193 was in my inventory for 20+ years.

Besides, I was having fun. Cycling was robust if not actually forceful. Three-shot accuracy from a sandbag rest was a surprising and very respectable quarter-covering 0.7" at 75 yards. I also tried the suppressed gas selector position but without a suppressor mounted, and the bolt short cycled; empty cases ejected fine, but rearward bolt travel was not sufficient to pick up and feed the next round in the magazine.

The customer wanted a hand stop fitted to the BRN-180 assembly, but it could not be mounted as far forward as possible due to the double-row of gas vent holes drilled circumferentially in the gas cylinder. I didn’t want to risk burns by holding the hand guard in the area of the gas vent holes, and I admit that I can’t say if risk of burn injury is real or not.

But discretion being the better part of valor, a Magpul M-Lok hand stop kit was installed on the bottom face of the hand guard just behind the gas vent area of the upper. Another point about the gas vent ports: It doesn’t take long for the alloy hand guard to warm up. At the risk of being taken for an operator operating operationally, it is recommended that the weak hand wears a glove when one shoots a BRN-180 equipped rifle for more than a couple-few 30 round magazines.

One criticism of Brownells—the instruction sheet packed with the BRN-180 had the appearance of being the product of a photocopy of a photocopy of a photocopy about 50 trillion times; it was practically unreadable. This is a little surprising in this litigious day and age. One would think that Brownells and its partners would want the instructions as clear and legible as possible. All together, the BRN-180 with stock and lower receiver tipped the scale at exactly 6.8 pounds without a magazine fitted.

That’s remarkable for a piston-operated 223/5.56 rifle with the benefit of being an updated proven 50+ year old design. The assembled rifle has a perfect balance point at just in front of the magazine well with no magazine installed. The customer is extremely pleased with the outcome, and reports that he’s enjoying depleting his own decadesold 223/5.56 ammo reserve.

This particular weapon as-assembled just works, and as a former owner of both a Sterling Armament-built AR- 180 and a Arma Lite AR-180B, I’m contemplating ordering a BRN-180 upper for a build of my own. AG