Build Your Legal HK416 Clone With the Brownells BRN-4

Build Your Legal HK416 Clone With the Brownells BRN-4

Brownells is the MAC Daddy of the modern American gun world. They offer untold tens of thousands of gun-related items ranging from reloading supplies to ammunition to live weapons to a simply bewildering array of firearms parts and accessories. Amidst all that intoxicating gun swag, Brownells also sells a little unrefined unobtainium.

Build an HK 416 Copy With the Brownells BRN-4 Upper

No kidding, I have in my own collection a BRN-Proto. If ever you lusted after a spot-on rendition of the original 1956-era Gene Stoner AR-15, this was the only show in town. While Brownells no longer sells these complete rifles, they do offer parts for the creative gun bodger with a little mechanical aptitude and a credit card. The latest breathtaking creation to come out of the Brownells skunk works is the BRN-4 upper.

America is covered in a thin patina of AR-15-variant rifles. Why should a standalone drop-in upper receiver warrant any special attention? That would be because you can use this upper to legally craft the finest terrorist-killing machine ever devised by mankind. With the entire world as your gun store, this is as good as it gets.

War Story

At 0100 on 2 MAY 2011, a group of two dozen exquisitely-trained SEALs from the Naval Special Warfare Development Group assaulted Osama bin Laden’s fortified compound in Abbottabad, Pakistan. They inserted via a pair of highly-modified MH-60 stealth Blackhawks. The CIA had been hunting bin Laden relentlessly for a decade. They ultimately determined his location through some simply epic clandestine field work. When it came time to administer a little frontier justice, these SEALs queued up to do the deed.

American Special Missions Units employ the finest shooters on the planet. They clear structures like artists. Their medium is the controlled application of overwhelming violence. 

It really all came down to raw unvarnished chance. The SEALs of DEVGRU’s Red Squadron started with the guest house on the first floor of the compound where they killed an armed terrorist and wounded his wife. From there they moved up through the structure, sterilizing levels and clearing rooms as they went. At each juncture, SEALs peeled off to secure their assigned spaces. By the time they got to bin Laden’s bedroom on the third floor, Rob O’Neil and Matt Bissonnette were the shooters on deck. 

The specific details have been disputed and don’t really matter. The CIA had cut the power, so the interior of the building was pitch dark. The SEALs sported state-of-the-art NVGs, so they didn’t much care. 

The most compelling version had bin Laden leaning out into the hallway behind one of his four wives. Bin Laden was a large man. At six-feet, five-inches-tall he towered above the diminutive woman. According to the story, one of the SEALs popped him twice in the forehead with a pair of Black Hills 77-grain Open-Tipped Match 5.56mm rounds. The most wanted man on the planet was dead where he dropped.

From top to bottom we have the BRN-Proto, the BRN-4 version of the HK416, and the hybrid BRN-180. For radically cool weapons like these, Brownells is the only show in town.

The Gun

The weapon that these Navy SEALs used to send Osama bin Laden straight to hell was the HK416 assault rifle. Designed as a collaborative effort between the shooters of the US Army’s Delta Force and Heckler and Koch, the HK416 is recognized as the finest combat rifle in the world. Everything about this rarefied weapon is optimized for close quarters battle.

The gun could pass for a slightly-modified M4 carbine in dim light, but there is so much more to it than that. The weapon operates via a short-stroke gas piston-driven system that very effectively keeps gunk and fouling out of the receiver. As a result, it is a bit heavier than an M4, but the action is essentially unstoppable. A friend who spent more than a decade as a Delta operator once told me they would start a three-month deployment with spotless 416’s, shoot most every night, and then clean their weapons again for the first time when they got back to Bragg. The HK416 is the finest combat rifle mankind can produce. And you and I aren’t supposed to have them.

The HK416 (top) and the Brownells BRN-4 are essentially the same gun. The biggest difference is that the BRN-4 is actually available to American civilian shooters.

HK Hype!

It’s not that the HK416 is any more lethal or dangerous than a $500 M4 clone. It is simply better in most every conceivable way. The ergonomics are essentially the same, but the gun is monotonously accurate and as rugged as John Wayne’s jockstrap. For reasons I never have really understood, HK won’t sell them to us. That supposedly has something to do with German export laws.

You can get a sort-of clone of the 416 from HK in the form of the MR556, but it has a long barrel and a semi-auto bolt carrier. Up until recently if you wanted a proper short-barreled version of the gun that killed Osama bin Laden, you had to find a police SWAT team someplace getting rid of theirs and build up the de-milled parts kit on a virgin receiver. That’s where I got mine, but it looks like it has been in service since Moses was a Private. That gun also cost more than my first car. Now, thanks to Brownells, you can build up a real-deal 416 at home out of brand-new parts. I was giddy at the prospects.

The Brownells BRN-4 is a DIY version of the same extraordinary HK416 rifle that the Navy’s DEVGRU used to kill Osama bin Laden. It is an incredible weapon.

Brownells BRN-4 Details

I compared the BRN-4 alongside my original high-mileage HK416, and they are indeed the same gun. The particulars are identical. Brownells offers their BRN-4 uppers in 10.4-, 13.7-, and 16-inch versions. Chrome-lined barrels are also an option. I wanted to recreate the bin Laden gun, so I opted for the short barrel and a registered SBR (Short-Barreled Rifle) lower receiver.

The upper comes without a handguard, but Brownells can hook you up. Mine came from Geissele Automatics and is interchangeable with that of the HK416. Everything was plug-and-play into my Palmetto State Armory M4A1 registered SBR lower receiver.

The BRN-4 demands a slightly different maintenance regimen when compared to your more pedestrian M4. Removing the handguard involves turning out a single screw. The screw slots are designed to accept the lugs on the bolt like a wrench, so you don’t need any ancillary tools. That gets you to the gun’s entrails.

As the weapon is piston-driven, the bolt carrier doesn’t need a gas key. The lug against which the piston impinges is machined into the assembly as a single unit, rendering it legit indestructible. The BRN-4 also incorporates a spring-loaded firing pin for added safety. 

The short-stroke piston-driven action of the BRN-4 represents a quantum improvement over the legacy direct gas system of the original AR-15.

Trigger Time

I slapped a SilencerCo Velos sound suppressor on the snout, a Trijicon ACOG up top, and a superlative Streamlight TLR-8 combination light and laser on the rail along with a broomstick grip. Thusly configured, the gun is indeed slightly heavier than a conventional M4, but it is rock solid on the range. I can see why the SEALs and Delta love theirs. 

The gas system is not adjustable, because it doesn’t need to be. It ate everything I stuffed into it without a hiccup. Even after a zillion rounds, the interior of the gun remains unnaturally tidy. A direct gas impingement M4 subjected to the same abuse would look like the grease trap at the local Jiffy Lube. You cannot kill this thing. Trust me, I tried.

The SilencerCo Velos excises all the bark out of the gun, and the rest of the cool-guy stuff keeps me prickly indoors or out, day or night. Fired from a simple rest at typical CQB distances, I could keep my groups the size of a dime. Make that offhand, and I could still cover them with a juice can lid. Running this gun while on the move will illuminate the vast difference between truly epic quality and everybody else.

Disassembly of the BRN-4 involves turning out the single screw on the handguard. The bolt lugs serve as a wrench for this purpose.


At $1,199 for the upper without a handguard, the Brownells BRN-4 is not cheap. However, when compared to other high-end black rifles, it’s not unduly expensive, either. You can trick out the whole gun from scratch and still not have as much cash invested as you might for a nice Steyr AUG or an FN SCAR, both superlative close quarters weapons in their own right. 

The fact that the BRN-4 is a relative bargain really doesn’t matter, because it is indeed the only show in town. If you want a part-for-part clone of the HK416 rifle that offed the world’s apex terrorist, this is the only way to get there from here. The design and execution of the BRN-4 are simply magnificent.

Whether the rifle rides in your squad car, behind the seat in the minivan when out where the Wild Things Roam, or safely secured in your bedroom closet, the BRN-4 is literally as good as it gets. Within the constraints of American firearms law there is simply nothing better. Building it up at home requires very little talent, and the thing runs like a politician after money. Yet again, Brownells has hooked us up with the cool-guy stuff you just cannot get anyplace else. I could kiss them for it.

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Brownells BRN-4 bolt carrier group.

Brownells BRN-4 Specs

  • Caliber 5.56x45mm
  • Barrel Length 10.4 inches
  • Overall Length 28 to 40.6 inches collapsed and extended
  • Weight 8 pounds
  • Action Gas-Operated, Short-Stroke, Rotating-Bolt Piston- Driven
  • Feed STANAG Magazines
  • Suppressor SilencerCo VelosOptics (as tested) Trijicon ACOG

Brownells BRN-4 / HK 416 Shooting Results

Load Group Size (inches) Velocity (fps)
SIG Sauer 55-grain FMJ 0.2/0.4 2,504/2,428
Winchester 62-grain FMJ 1.1/0.4 2,685/2,597
Black Hills 77-grain OTM 0.4/0.3 2,395/2,318
Group Size is best four of five shots fired from a sandbag rest at 25 meters. Velocity is the average of three rounds measured by a Garmin Xero radar chronograph.

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Source link: by Will Dabbs MD at