Embedded Files
The Patent Battle That Decided Germany's Next Assault Rifle
Preface
In what may seem like an unusual departure from the German-language content on this site, I have decided to write this post in English for the benefit of any international readers interested in the Haenel vs. Heckler & Koch case. My hope is that it will serve as a reference for anyone wanting a clear breakdown on the events that led to the initial 2020 winner of the of the "Assault Rifle System" tender of the Bundeswehr, the Haenel MK556, being ousted and eventually replaced by Heckler & Koch's HK416A8.
If this is your first encounter with the Haenel vs. H&K affair, I recommend watching these two videos by the Military Arms Channel on YouTube for a general overview.
Part 1: Object of contention and timeline of events
Heckler & Koch (referred to hereafter mostly as H&K) holds a European patent (EP 2 018 508 B1, priority date of May 17, 2006) covering a breech locking system with one or more drain holes integrated into the recoil spring mechanism and bolt carrier. The purpose of this design is to allow fluids to escape upon rearward movement of the bolt carrier. Specifically, the return spring buffer is described being utilized in such a way as to expel fluids through one or more drain holes while the return spring is being compressed.
This feature is intended to provide what H&K calls "Over-the-Beach" (OTB) capability - the ability to rapidly drain any fluids which may be present in the system after being submerged in water. H&K famously demonstrated this in its Over-the-Beach Test of September 2005, footage of which remains widely circulated online.
When in September 2020 the German Ministry of Defence announced that C. G. Haenel had unexpectedly won the tender to replace H&K's long-serving G36 rifle with its MK556, the decision took many by surprise. H&K however soon suspected that Haenel's design might infringe upon its OTB patent.
In April 2020, H&K had procured a Haenel CR223 (4a O 68/20), a commercially available civilian rifle based on the MK556, and upon examination concluded that the weapon featured similar drain holes both in the buffer tube and bolt carrier, which they deemed a violation of the patented design.
This would set off a chain of events that would ultimately derail procurement of the MK556 before it had even truly begun.
According to a statement issued by the German Federal Ministry of Defence on October 10, 2020, H&K formally petitioned the Federal Procurement Office, alleging patent infringement and demanding a review. In response, the office suspended the award and reopened its evaluation of all offers - effectively freezing Haenel's win right on the finish line.
Having achieved this interim goal, H&K proceeded to file a lawsuit against Haenel in October 2021, citing patent infringement of EP 2 018 508 B1 and submitting their CR223 sample as evidence. On November 16, 2021, the Regional Court of Düsseldorf (LG Düsseldorf) ruled in H&K's favor, ordering the recall and dismantling of affected rifles (4a O 68/20).
This ruling, however, was widely misreported by media outlets at the time as a total recall of all CR223 rifles. In its own press statement, Haenel clarified that H&K had first raised the issue as early as February 2018, and that by June 2018, Haenel had already begun replacing buffer tubes (likely sourced from Oberland Arms), which featured three rearward and three underside drain holes.
It's important to note that the rifle found to infringe the patent (pre-2018 CR223) and the MK556 entered into Bundeswehr trials were technically similar but not identical. In all likelihood, the latter used a single, centrally located rear drain hole in the buffer tube (in the style of M4 receiver extensions) - or possibly none at all.
Naturally, Haenel did not take the accusations lying down. On December 12, 2020, the company had already filed for annulment of the patent in question with the Federal Patent Court (Bundespatentgericht) in Munich.
Buffer tube and bolt carrier of H&K's CR223 sample showing drain holes (left), compared with Figures 3–5 of EP 2 018 508 B1 (right).
The challenge succeeded only in limited form: After nearly two years of proceedings, the court ruled on September 30, 2022 (BPatG München 7 Ni 29/20) that H&K's patent would remain valid - albeit effectively limited in scope to short-stroke gas piston systems and valve-less drain holes. During the case, H&K itself had narrowed its claims, and the court upheld the patent within those boundaries.
Meanwhile, Haenel appealed the 2021 LG Düsseldorf ruling to the Higher Regional Court (OLG Düsseldorf), hoping to overturn it. But after awaiting the outcome of the patent validity case, the OLG also sided with H&K in its decision on December 30, 2022 (15 U 59/21), stating:
"Zu Recht hat das Landgericht festgestellt, dass die angegriffene Ausführungsform unmittelbar von der technischen Lehre des Klagepatents Gebrauch macht und der Klägerin die ihr daraus resultierenden Ansprüche – in eingeschränktem – Umfang zugesprochen." (engl.: "The Regional Court rightly determined that the contested embodiment makes direct use of the technical teaching of the patent in suit and therefore granted the plaintiff the claims arising therefrom – to a limited extent.")
Part 2: Opinion Piece - Why the OTB Patent should have been invalidated
It is undisputed that drainage holes as a concept in AR-15-derived rifles predates H&K's 2006 priority date. Buffer tubes intended for "OTB" capability and maritime use already featured drilled holes to let fluids escape.
This is the crucial point: The Higher Regional Court (OLG Düsseldorf) accepted that "front" and "rear" drain holes are not distinct categories but rather variations of the same functional concept, regardless of amount or exact position within the system. As the court stated:
"Dem Klagepatent ist insoweit keine Unterscheidung zwischen (vermeintlich verschiedenen) Fluid-Durchtritts-Öffnungen zu entnehmen (...)" (engl.: "The patent in suit does not disclose any distinction between (supposedly different) fluid passage openings (...)"
If "a drain hole is a drain hole", then earlier buffer tube drain configurations (such as the center hole used in the M4A1 carbine by Colt) come much closer to the core of H&K's OTB patent. It would have been reasonable to argue that taking a known drainage concept and applying it (using multiple openings) to the usual AR(15/18) architecture is - plainly - obvious, especially since the patent's own description gives so little detail beyond suggestions for positioning and number of holes. The mentioned drainage time of one to three seconds constitutes a goal, but not a technical feature of the invention in and of itself.
The US Army's technical data package (TDP) specification for the M4A1 features a drain hole in the receiver extension / buffer tube as early as 1986.
Commercially available buffer tube by Oberland Arms with identical drain hole arrangements.
Noteworthy: Buffer tubes identical in function to those used in the disputed CR223 remain readily available on the German civilian market today (by the same company no less) - albeit as components for standard internal piston ("direct-impingement") AR-15 rifles, rather than short-stroke gas piston systems. In other words, the same drainage concept continues to circulate freely outside the narrow scope of H&K's patent protection.
One might respond that this is hardly surprising, given that H&K's patent explicitly emphasizes the short-stroke gas system, a focus also underlined in the subsequent court rulings. Yet this raises an obvious question: Isn't the short-stroke gas piston system entirely incidental?
The actual teaching of the OTB patent lies in the concept of the drainage system: (valve-free) openings, interconnected internal cavities and the displacement effect achieved by the return stroke of the buffer.
This interplay could just as well be implemented in other modes of gas operation, such as long-stroke gas piston or even a Bang-style muzzle cup. The idea of displacement and rapid drainage of fluids is operating-system-agnostic, and ought to be considered an element of general engineering know-how rather than a unique embodiment of an H&K invention.
For the courts, the decisive issue was that the exact claimed combination of drain holes and short-stroke gas system had not been shown to be previously disclosed. However, if the operating system is completely incidental and drainage holes are nothing new either because they were conceptually used well before 2006, that would make the OTB patent a mere combination of known features. In my mind, the repurposing of already well-known drain holes for a short-stroke gas piston firearm does not constitute a non-obvious, inventive step, and thus, the patent should have been nullified. From an engineering standpoint, the claimed solution simply seems too close to what any skilled designer familiar with maritime requirements and AR-derived patterns would have done anyway.
What to make of it all? As the saying goes: When you come for the king, you best not miss. And come for the king C. G. Haenel certainly did. In the end, this appears to have turned out less a contest of innovation rather than a textbook example of lawfare and a demonstration of using legal means to reassert market dominance under the guise of patent protection.
Political overtones were never far away either. At the time, several public political figures voiced ostensible concerns about awarding the contract to a subsidiary of Merkel, itself owned by Caracal International in the United Arab Emirates. Those objections likely contributed to the outcome by reinforcing institutional caution. And the subsequent court rulings only deepened the unspoken but prevailing belief that Heckler & Koch - having supplied every Bundeswehr service rifle to date - should have simply been awarded the contract "by default".
Google Sites
Report abuse