H&K Factory Tour With Exclusive Preview of the Next Generation HK433 Rifle

By Dickson Ly

Germany has a world renowned reputation of producing high quality, high tech goods. From automobile manufacturers such as Mercedes Benz, Porsche, BMW and Audi to Bauhaus, designs that inspire companies like Tesla and Apple, the phrase “German efficiency” and Germany’s general design philosophy of function over form is heavily engrained into people’s minds worldwide. What the general public, including most German citizens, are not aware of is the fact that the small southern town of Oberndorf contains one of the best small arms manufacturers in existence today.

It is not easy for the average person to gain access to the Heckler & Koch (H&K) factory. I was lucky enough to be invited by Sandra of H&K International Sales, Civilian Market (excluding USA) for a 2-day tour that included a factory tour of the production area, H&K Showroom, H&K Museum as well as the Mauser Museum located offsite in downtown Oberndorf. The tour concluded at their private shooting range about 45 minutes offsite, at which I tried various fully automatic small arms.

Heckler & Koch have a long track record of providing reliable firearms to Special Forces and military units of countries around the globe. The MP5 is the most recognizable and iconic product offered by the company, first recognized in the public eye at the London Embassy Siege where it is still in high demand by various military and law enforcement agencies today. To understand H&K, we have to go back to cover a bit of history.

The town of Oberndorf is where the famous firearm manufacturer, Mauser, once was based. The company was founded in 1811 by Wilhelm & Paul Mauser. The location was chosen due to a low rate of employment in the town and because they could make use of the river, by which the machinery could be powered by the constant stream of water. They manufactured bolt action rifles and semi-auto pistols for the German army as well as export to countries around the world including China and Japan.

Mauser was the first to manufacture the 13.2x92mm anti-tank rifle in 1918 when French and British tanks first emerged in World War I. After the war, the company was forbidden to produce firearms so it produced automobiles and sewing machines in order to survive—there are examples of these in the Mauser museum.

Some of the Mauser engineers moved to Spain after World War II to develop the CETME rifle in 7.62x51mm. The design was then further developed when some of these engineers moved back to Germany. The rifle evolved into the G3 when two ex-Mauser engineers, Edmund Heckler and Theodor Koch, founded Heckler & Koch on December 28th, 1949.


Many manufacturers claim they produce everything in-house, but often times the term “in-house” is marketing speak, and the definition is quite unclear. In the case of Heckler & Koch, they really do mean it. They have an area for raw materials such as the special steel needed to produce the bolt and barrel and various 20-plus-foot-long aluminum tubing that is to be machined into handguards and receivers.

The first thing the technicians do in the morning is to check and gauge all of the tools and bits to ensure they are not worn or broken. There’s a dedicated room on the shop floor just for this. All of the technicians are dressed in black polo shirts with the H&K logo on the left breast.

The production floor is filled with CNC machines spread across the width of the building, each one lined up perfectly, and they are connected to a conveyer belt system. On one side, aluminum blanks are inserted in multiple rows and columns. The robotic arm picks up the blanks and inserts them into the CNC machine. When the machining process is complete, the arm will put the items back onto the rack and repeat the process again for the next blank. This type of automation reduces time by reducing human interaction as the machines are running 24/7.

Despite seeing the amount of automation at the production floor, there’s a dedicated area for a dozen technicians to do deburring of sharp edges by hand on the upper and lower aluminum receivers, using a tool that makes the same high pitched whine as a dentist tool. There is also a final QC area where random pieces from each batch are checked to ensure they are within the dimension tolerances.

I was genuinely surprised that they produce their own polymer receivers and other polymer parts in-house, which is a monumental task by itself. The area has the distinctive smell of plastic formed when the finished product comes out of the mold. Polymer parts create less waste since there are no excess aluminum chips or bits to accumulate from machining. The time to produce polymer is also much less compared to metal parts which is ideal for mass production. Very impressive indeed.

The barrel is a critical part of any firearm. H&K has a total of three cold-hammer-forging machines and also a fourth one off-site for making the 40mm barrels. The advantage of cold-hammer forging compared to button-rifled is added strength and extended longevity.

One of the important steps that many barrel manufacturers overlook is barrel straightening. The barrel is often not perfectly straight once the hole has been drilled through it. The technician checks to see if the barrel is straight by using an optical laser. The barrel will then be placed on a barrel press and bent back into perfect straightness. Simply put, it’s an extremely time consuming process. This is a form of art that requires many years of experience to master. H&K had a machine to automate the process, but it had flaws. In the end, they reverted back to doing it manually. It’s interesting to note that the barrel press machine is the exact same one displayed at the Mauser museum.

Interestingly, the factory is currently producing parts for the mid-life improvement upgrade to the British SA80 or L85A3. The company is producing upper receivers finished in OD Green. The new design is stronger with welding in several areas and a long Picatinny rail for optics. This will further extend the life of the rifle beyond 2025.

H&K is also very busy fulfilling the French contract of the 102,000 HK416F rifles for the Army, Navy and Air Force until 2028; they’re receiving additional orders from the US Army on the M27 IAR, in addition to competing for the German Army tender. Which brings us to the most important subject of this article–the next generation HK433 rifle.


On range day I was delighted to see the HK433 prototype resting calmly on the table next to the G36 and 416. I was introduced to their military sales representative, who was friendly and told me we were in no hurry. In order to understand the HK433, he first explained the gas systems of the G36 and 416 designs. Using a G36 made of transparent plastic, he showed me the inner workings of the G36 short stroke gas piston system of which the hot gas coming out of the barrel’s gas port goes up towards the piston. The piston, which is finished in hard chrome, pushes the rod which then pushes the bolt carrier back to extract and eject the spent case. The advantage to this is the bolt remains cool to the touch; in addition the hot gas moves towards the muzzle which means the bolt does not get dirty compared to a direct impingement gas system like the M4/AR15. That design was put into the 416 when the company was being asked by their customers to upgrade the M4. In fact, the piston and guide rod designs are very similar on both the G36 and 416.

The multi-lug bolt and bolt carrier are largely similar to the G36, with the exception that the guide rod is now attached to the bolt carrier. It also features a firing pin safety like the 416.

He made it clear that the HK433 was already in development before the German government had shown any signs of replacing the Army’s G36 rifles. In fact, the new rifle’s requirements from the German Army tender have not been officially released. He further explained to me that they have strong relationships with the right people in the German government, and they were able to get some general ideas of what they are looking for.

Since the G36 is an ambidextrous rifle designed for both left and right hand use, the same applies on the HK433. The ambidextrous safety levers are in the exact position as the G36, and the magazine release paddle is also in the same location behind the magazine. The magazine release paddle is easy to manipulate even for a long-time AR15 user like myself. The ambidextrous bolt lock and release is located between the magazine and trigger guard for easy access. The bolt locks by pushing the button upward with your index finger and pulling the charging handle rearward. Once the bolt is locked back, it releases by pressing the same button downward. On the G36 the bolt release is inside the trigger guard, and H&K had to move it away from the trigger guard due to the new tender’s requirement.

The rifle is also designed for the user to manipulate the safety and fire the rifle with the stock folded. With the G36, the safety was difficult to manipulate for a left hander; with the collapsible stock all the way in the first position it blocks the ejection port so rounds will not be able to eject. They have corrected this with the 433 with the stock folding at an angle away from the ejection port and slimming down the stock profile for easy access to the safety lever.

The HK433 uses STANAG or NATO magazines designed for the 416 and M4/AR platforms. The main reason was dictated by gear. The polymer G36 magazines are simply too bulky, and due to their design, they are difficult to insert and remove from magazine pouches. The STANAG magazines stack nicely in double magazine pouches, and H&K’s are made of steel which are stronger than the original aluminum body.

One of the issues with the G36 is the customers are having trouble with mounting optics. In the later versions, H&K removed the fixed carry handle and had a Picatinny rail installed for those who prefer to use their own red dots or magnified optic. However, due to the location of the charging handle, they are not able to lower the rail so the high bore axis created problems. If one were to shoot behind cover, such as a vehicle, the shooter had to raise his rifle well above cover in order to avoid shooting the cover itself instead of the target. The final decision was to move the charging handle forward above the barrel and closer to the muzzle. It can be quickly removed and mounted on the opposite side with no tools. Like the G36 charging handle, it can function as a forward assist by unfolding and pushing it in. After the first shot is fired, the charging handle folds itself from recoil. The charging handle is non-reciprocating.

He pointed out to me that based on H&K’s research, the distance from the stock to the eye is on average 55 millimeters. The stock is adjustable for length of pull as well as cheek height. The cheek piece has three positions, and at the lowest setting works best with the foldable iron sights. At the lowest setting it can work with an optic such as the EoTech, but ideally you want it to either be at the highest or the middle position as it is more comfortable this way. The cheek piece is angled in such a way that it actually moves slightly forward as it rises. It is also sloped upward towards the upper receiver like the MP5 and G3, and it is more comfortable to lean your face into the gun compared to the 416 or other AR platforms.

The overall handling of the 433 is very good. Unfortunately, I was only able to handle it and not able to fire the rifle even though we were at the shooting range. The rifle is a tad heavier than the all-polymer G36, but it is not as heavy as the 416. To me, the 433 is better balanced than the 416 which is front-heavy even in the short barrel configuration. With the bolt carrier design similar to the G36, I can only imagine that it also shoots like a G36 in the sense that the recoil impulse is very controllable in 3-round bursts. With the right stance and control of the rifle, muzzle rise is very minimal, and there’s no problem hitting a man-sized target out to 100 yards in both semi-auto and controlled bursts.

It does resemble modern rifles from other manufacturers such as the FN SCAR and Bushmaster ACR. However, there are only so many ways to design a new rifle with improved ergonomics.


It is quite eye opening to witness the inner workings of a large military small arms contractor such as Heckler & Koch. At no point during my visit did any of the employees make any claim about being the best. It was apparent that the people I met were all proud of working for the company, but they were also extremely humble. The company definitely has a bright future ahead of it. I do believe, based on the HK433, it can outperform its competitors (with the likes of FN SCAR, Rheinmetall-Steyr RS-556 and Sig MCX) on the German tender due to its extensive experience over the years of manufacturing small arms. Drawing from that, I also foresee the rifle will be offered to other military and police units. Stemming from that there is hope for a civilian version of the rifle for the commercial market like the SL8 and newer HK243.

This article first appeared in Small Arms Review V21N9 (November 2017)
and was posted online on September 22, 2017


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