Brownells Reintroduced the Legendary BRN-180
It is hard to believe the AR-180 has become a somewhat forgotten firearm, however Brownells is bringing it back to the market in a complete BRN-180 upper format. The BRN-180 was a collaborative design effort between Brownells, PWS, and FM - Foxtrot Mike to bring back a modernized version of the often forgotten short-stroke driven AR-180. As a writer for Primary Weapons Systems and Brownells, I was privileged to have very early knowledge in 2018 of the new BRN-180 development. I was excited then, but have been thrilled with my long-term review of the flawlessly operating BRN-180 upper. For those interested in short barreled rifles and pistols, Brownells now has a short 10.5-inch barreled BRN-180S as well. What makes these unique guns so cool and why is the AR-180 style platform getting hot again? The short answer is the insane short-stroke piston driven reliability of the platform.
The original AR-180 is sort of like an AK and an AR hooked up and had some type of weird love child that has more AK DNA than AR. On the outside from a distance it looked a lot like an AR with similar ergonomics down to a very similar handguard front sight...etc. Up close, it was apparent that nearly every part was based on stamped steel construction similar to the AK but to a level far more detailed and complex than the simplicity of an AK. Though the AR-180 starts with AR it was not cross compatible with the AR15 platform, however the design of some parts was carried over in to a cost effective likeness. Of note the use of stamped construction was extensive including nearly every firing and operational control of the AR-180 gun in addition to the visible proprietary magazines and receivers.
The platform also has the ability to get really short with a folding stock like an AK thanks to the dual captured internal spring and rod set nestled inside the upper receiver and the obvious omission of a buffer spring. Internally there was also a very short and light bolt carrier with a reciprocating right handed charging handle again like an AK. One of the extolling features was an exceptional buttery smooth operation of the mini-carrier sliding on the dual spring and rod configuration. The AR-180 bolt is an AR15 style bolt and barrel lockup design, but the overall AR-180 or BRN-180 design does not permit barrel swaps. The AR-180 was also incredibly simple to operate with a large easy to find right handed reciprocating bolt handle to the similar to an AK.
The AR-180 was also one of the first short stroke piston driven AR-style platforms and it was famous for literally running forever without maintenance. With zero debris blowing back into the action, the gun stayed clean and could run perfectly between very long extended cleaning intervals. Allegedly, there are still some original AR-180 that have never been cleaned and run perfectly. In essence, the AR-180 was the Americans stamped steel receiver set equivalent to the AK but with a short stroke piston system. Today the AR-180 are prized collector items and many future guns based their design on the short stroke piston system including G26, SCAR, and 416 rifles and continues to influence many modern rifle designs including some aspect of very futuristic guns like the Tavor.
AN UPDATED LEGEND
The original AR-180 gun was budget focused, not super sexy and had the stamped, folded and welded quality of a very average AK. At that time, the vast majority of manufacturing was based on old stamping and folding machines that offered cheap production. At the same point in time, the milling required for the AR-15 format was quite expensive. Today that cost equation has flipped due to the old stamping tooling technology becoming discontinued and the greatly reduced cost efficiencies of current production CNC milling. The reality of the original budget friendly AR-180 was it was a bit crude with proprietary firearm parts and magazines, but it worked flawlessly.
Brownells, PWS and FM delivered an updated AR15 compatible upper which carries through the functionality and DNA of the AR-180 in a complete BRN-180 upper. The BRN-180 features modern billet machining, design, finish, quality, and accuracy all in a AR15 lower compatible format which represents a giant leap in quality over the old AR-180 design. The AR-180 was circa 1960s industrial looking where the BRN-180 could be mistaken for one of the most modern looking AR-15s on the market. This is a premium-tier upper that is extremely reliable long-running and cross compatible with any AR15 lower you have in your safe. The BRN-180 design is something that the market has been asking for… a 5.56 AK upper for your AR.
If you were going to redesign a piston powered rifle such as the AR-180, the market leading Primary Weapons System would be the clear choice. Dean Sylvester is widely regarded as the industry expert in AR format piston systems including developing their own PWS long stroke piston rifles famed for incredible reliability and elite tier quality. From my perspective, Brownells make the best choice of who to partner with.
The DNA of the AR-180 was preserved in the BRN-180, including some parts so similar they are hard to tell the difference between them. The dual springs and guide rods are still there as is the short stroke piston system, reciprocating right-handed bolt handle, easy disassembly, buttery smooth action, three-pronged flash hider, and no need for any buffer tube assembly. The biggest departures from the original design is that the BRN-180 is only a complete upper and not a complete gun and a design based on modernized AR15 compatibility. That modernization includes a free-float handguard, 5.56/.223 compatible match grade .223 Wylde chambered barrel, adjustable gas block, and of course the precision fit of modern machining.
Having the BRN-180 mate to a standard AR15 also allows customers to do all the customization they want an a standard AR15 without having to worry about compatibility of yet another firearm platform. According to Brownells, the AR15 compatibility greatly reduced the cost and instead of a full $2700 gun, they are able to retail a complete upper with match grade .223 Wylde chamber for around $800. This is not bad considering many piston ARs are easily retailing over $1800. Brownells has now introduced a BRN-180S, for “short”. The 180S will feature a 10.5-inch barrel and a slightly modified gas block to accomodate for increased dwell time and more adjustment for suppressor use.
DISASSEMBLY
The take-down is similar to the original, but has a buffer block that is friction fit to the rear of the upper receiver. That buffer block is easily popped out during the bolt removal process. Remove the rods and springs, pull back the bolt, remove the reciprocating bolt handle, and remove the bolt carrier group. According to Brownells, that is really all the typical maintenance requires. Advanced maintenance is also simple - remove the handguard u-latch, slide off the handguard, remove the linkage rod, the piston cup, and then the piston rod assembly for deep cleaning. Notably after several thousand rounds, I still see no need for any bolt cleaning and certainly nothing that needs cleaning on the piston side… this is one extremely clean running gun. The barrel is permanently mounted using a trunnion system to 180 ft/lb.
MAJORPANDEMIC.COM BRN-180 BUILD
For my build I used my BRN-M16A1 prototype build from a few years back. The Brownells lower was originally completed with Magpul furniture, Clark carbon fiber handguard, HyperFire, and Ace Stock all around the concept of what could have been from a manufacturing perspective, but with modern design ideas.
New updates to the build were a Brigand Arms Carbon Fiber stock and PWS ratcheting castle nut which are still things that could have been. On the BRN-180 upper a 34mm Burris 1.5-8 XTRII with a Geissele Super Precision mount.
The accuracy results were impressive with solid 1-inch 100-yard groups and several groups nudged into the .75” range. What I really love about the BRN-180 is that I can hand it to anyone and within a few seconds, it is obvious how to charge and operate the gun. For new AR shooters this can take a moment or two. I also like that the BRN-180 is absolutely an AK-gunners paradise in an AR platform with over or under bolt operation that mimics the AK function. Functionally this upper is a tank that has yet to see even a patch pull through the bore after my initial cleaning - wonderfully reliable.
BRN-180 SPECS
BRN-180™ has 16" barrel with matte black Nitride finish
BRN-180S™ has 10.5" barrel with matte black Nitride finish
Ultra-reliable AR-180 piston operating system
Compatible with current mil-spec AR-15 lowers
Machined 7075 T6 aluminum receiver & handguard - hardcoat anodized finish
.223 Wylde chamber
Button rifled bore; 1-8" twist
1/2"-28 threaded muzzle
Replica 3-prong AR-180 flash suppressor
Molded polymer ejection port cover
The BRN-180™ and 180S™ upper receivers are fully compatible with any standard, mil-spec AR-15 lower receiver
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BRN-180S
Gasblock: Adjustable
Barrel Length: 10.5"
Length: 18.57 inches
Weight: 4 lbs
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BRN-180
Gasblock: Adjustable
Barrel Length: 16"
Length: 24.57 inches
Weight: 4.65 lbs
Short Stroke Gas Piston: Designed for maximum reliability, the short-stroke gas piston keeps fouling out of the receiver and lets the bolt run cool and clean. The BRN-180S™ has a fully-adjustable gas block for shooting either suppressed or unsuppressed.
Bolt Carrier & Recoil Guide Rods: True to the original, the bolt carrier rides on twin recoil guide rods for a smooth, light recoil impulse. The recoil system is completely self-contained in the upper.
Bolt: The BRN-180™ bolt features a matte black oxide finish for easy cleaning and corrosion resistance. Classic multi-lug rotating bolt ensures reliability and repeatable lockup.
BRN-180S Flash HiderFlash Hider: The 3-prong flash hider gives an authentic look, while also effectively reducing both muzzle flash and rise. The closed bottom reduces the amount of dirt and debris kicked up by the muzzle blast.

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10mm Is Coming Back and is Smart for PCC - Pistol Caliber Carbines
If you know the background development of the 10mm round, you might know that it was developed as a high power semi-auto round ultimately selected by the FBI. The problem was that the 10mm round was actually too powerful for the majority of the agents to actually carry, train with and shoot comfortably.
The 10mm round has a cult following that is increasing with the Glock G20 still being a strong seller and other manufacturers like Rock Island, Para, Wilson, Sig, Kimber, and others all offering 10mm models as well. With the popularity of PCC - pistol caliber carbines, the 10mm power makes a huge amount of sense for very short PDW type pistols.
BRIEF HISTORY OF THE 10MM AUTO
The development of the 10mm round is actually an interesting story which dates back to the 1970s. The idea was for a high power flat shooting semi-auto cartridge that would run in a 1911 format pistol which would basically deliver .357 to .44 Magnum (midweight loads) ballistics. In the end, Jeff Cooper, yes the scout rifle guy, was involved in the development at which point Norma began producing ammunition in the early 1980s. The FBI felt a little outgunned on the streets and briefly adopted the 10mm round, but with the full bore kick ass loads that were first released, they felt it was just too much.
The reality was 90% of the agents felt uncomfortable shooting and handling the larger dimensioned and significantly more powerful 10mm powered guns. The ammo manufacturers responded with the 10mm Lite rounds which in essence dropped the power all the way down to really hot .40 S&W loads around 550 ft/lbs of energy at the muzzle.
The FBI and the public wanted a smaller format with less power than what the 10mm round delivered. Smith & Wesson thought this was a waste of unused powder space on the longer 10mm brass and developed a 10mm Short or what we now know as the .40 S&W. The round delivered everything the FBI specs wanted in a format that would fit in a smaller 9mm sized pistol format.
The current crop of 10mm rounds from Hornady and others are not neutered to the degree the "LITE" rounds were, however they could certainly be loaded hotter as we see with the higher power 1,350fps and 728 ft. lbs of energy Buffalo Bore rounds and the very unique LIbery Ammo with a 60gr bullet screaming along a 2400 fps delivering a whopping 780 ft/lbs. The current neutered 550 ft/lbs of energy 10mm rounds are still much more powerful than the average 360 ft/lbs of energy found in the .40 S&W. .40 S&W usually deliver around 360 Ft/lbs of energy and the normal off the shelf 10mm Auto loads typically delivery around 550 ft/lbs which is nearly 40% more power.

Today the 10mm cartridge still does have a following in Special forces and Special Law Enforcement and is growing as a hunting cartridge due to the capacity of the firearm and power. It is a favorite pistol for those hunting hogs and venturing into bear country.
5.56 7-inch Barrel vs 4-inch barrel 10MM
The 5.56 round is a wonderfully flexible round, however as with most shouldered cartridge rifle rounds, they are optimized for longer barrels and lose a ton of velocity with barrel lengths under 10-inches. In the case of a 5.56 7-inch AR15 pistol muzzle velocity and energy take a huge hit down to 2000-2200 fps velocity and 500-700 ft/lbs energy. A super short AR15 still delivers big power, but in contrast the 10mm is actually a better option.
Depending on the round, 10mm rounds were designed to deliver 500-770 ft/lbs energy and 1000-2400 fps out of a 4-inch barrel and out of an AR15 equivalent 7-inch barrel the round picks up about another 10% of velocity and a bump in power. The heavy fat round is designed as a pistol caliber which means it really will not pick up a lot more power with a longer barrel, where the light 5.56 round loses about half of its power in a 7-inch barrel. Of course there is also that deafening concussive blast out of a 7-inch barreled 5.56 AR15 pistol which makes it really impractical for home defense. With these points in mind, the argument could easily be made that a very compact 10mm PCC with a 4-inch barrel has the same or more power, in a smaller & quieter format, and that also accepts G20 pistol magazines is a better choice in micro PDW formats.
The 10mm PCC build pictured is based on a Glock G20 magazine compatible New Frontier Armory receiver set & .40 Caliber bolt, KAK 4-inch 10mm barrel, SB tactical brace, Hiperfire EDC trigger and Sig Sauer Romeo 5 red dot. At under 20-inches, this little PCC is a thumper and can get my steel targets rocking - a feat any of my AR15s cannot accomplish. With a LAW Tactical folding stock adapter instead of the SB Tactical brace, this little rig could be under 14-inches.
If you are not in the mood to build your own, New Frontier and others offer complete 10mm uppers and C45 lowers that have a combined cost of just under $1000 that only require you to push in the take-down pins. Retailers like Joe Bob Outfitters also have a variety of options as well for a DIY option at a reduced price.
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