In 1968 Heckler & Koch launched the HK33, chambered in 5.56x45mm, to compete with Colt’s AR-15/M16. The HK33, and later HK53, used the same roller-delayed blowback action developed for the G3 in the mid 1950s. However, few major contracts were forthcoming with the German military opting to continue using the 7.62x51mm G3.
Due to the modularity of the HK33′s design users could replace the butt of the standard rifle with a collapsible telescopic metal stock. H&K also subsequently designed a carbine version of the full-length HK33, the HK33K with a telescopic metal stock and 12.7 inch barrel. In the mid-1970s H&K began development an even shorter version. The result was essentially an intermediate calibre submachine gun similar to the Colt Commando and the Soviet AKS-74U. H&K designated this new weapon the HK53, it used the same telescopic stock as the HK33K and MP5 and a cut down 11 inch barrel, the HK53 also utilised a polymer forearm similar to the MP5s.
Like the HK33, the HK53 fed from 25, 30 or 40 round box magazines. The weapon weighed just over 3kg (7lb), almost a 1 kg less than its parent rifle the HK33. Unlike the HK33, the HK53 has a four prong flash hider. A number of police forces and militaries adopted the HK53 for a variety of roles. Special forces units around the world including the British SAS, Royal Military Police Close Protection Unit and Royal Marines, designated the L101A1 in British service, who typically used it during close protection duties and operations involving close quarter battle.
As shown in various MoD Equipment Failure Reports dating from the early 1990s the HK53’s in British service suffered from repeated damage and failure of the carbines’ locking rollers. This issue arose when using a number of different ammunition types including brass cased blank ammunition (H&K recommend the use of their proprietary blank cartridges). Following a meeting between the Army Technical Support Agency’s Directorate of Engineering and H&K a new design for the locking pieces were developed. These changes “increased the roll of blowback force during the unlocking phase… in turn this will reduce the mean energy of the recoiling mass of breech block and carrier” this was intended to reduce bolt bounce. The Royal Military Police Close Protection Unit’s L101A1’s were also fitted with a new two stage buffer within a fixed stock.
Due to its short length the HK53 also found itself pressed into the port-firing weapon role. Designated the HK53 MICV in this role the foregrip and stock was removed and a specially designed endcap and a spent case bag could be attachment. During its service life the HK53 went through a series of changes to furniture mouldings, buttstock types and fire selector options. It remained in production into the early 2000s, when Heckler & Koch replaced the HK33 and HK53 with the G36 and G36K.
Note: While this collection of images covers only the externals of the G11, rest assured that if and when we get the opportunity we will follow this up with hi-res photographs of the weapon disassembled!
Many thanks to the collection, which wishes to remain anonymous, that holds this example of the G11 for the opportunity to examine, photograph and film it.
Vic kicks off his series looking at the US Army’s ACR trials rifles with a look at, not one but two versions of, Heckler & Koch’s advanced caseless ammunition assault rifle – the G11. This video is an introductory overview, we’ll be delving into the G11’s insanely intricate and wonderfully complex action in later videos!
There are few experimental weapons that have cultivated myth and reputation like Heckler & Koch’s G11. The product of decades of research and development into what was hoped would be the next evolutionary step in small arms design. The G11 was Germany’s attempt to combine advanced caseless ammunition with a weapon system which could increase the average infantryman’s hit probability. The G11’s action has three distinct modes of fire and uses a complex action and buffer/recoil system to achieve a high rate of controlled fire.
The program began in the late 1960s as part of a NATO initiative, however, it became a primarily Bundeswehr project and over two decades the design evolved substantially. The project sought to increase the hit probability of the individual infantryman. Heckler & Koch’s approach to this problem was the most radical. Working with Hensoldt to develop an integrated optical sight and with Dynamit-Nobel to create a new kind of ammunition.
Numerous studies and theoretical designs were worked up but by the mid-1970s the base design of what would become the G11 was cemented. The design team included Gunter Kastner, Dieter Ketterer, Tilo Moller and Ernst Wossner – all of whom are credited in H&K’s 1976 patent protecting the G11’s rotary action.
The G11 went through dozens of iterations throughout the 1970s and 80s, with the first firing prototypes ready by 1974. Both the design and the ammunition also went through a number of changes.
The revolutionary ammunition was developed by Dynamit-Nobel AG.
The 4.73x33mm round which was finalised comprised of a solid propellant material body which encased a primer, booster, projectile and a plastic nose cap. Dynamit-Nobel developed the High Ignition Temperature Propellant (HITP) in an effort to prevent accidental ignition (cook-off) of the ammunition’s outer propellant body.
The G11 fed from 45 or 50-round horizontal, single stack box magazines which fed rounds into the action at 90-degrees. The rounds were then rotated into alignment with the breech by the rifle’s action.
The rectangular shape of the Dynamit-Nobel ammunition was more efficient and better suited to storage than conventional circular rounds. The positioning of the magazine along the top of the weapon, parallel to the barrel, also in theory helped minimise the rifle’s profile and reduce encumbrance for the soldier equipped with the weapon.
The G11 is a gas-operated weapon with gas being tapped from the barrel, to cycle the rifle’s cylinder drive system, which rotated the breech through a series of cams and gears. At the heart of the G11 is a complex rotary action. Rotating actions themselves are not a new concept with the earliest dating back to the 17th century, such as the Lorenzoni system.
The G11’s rotating breech was patented in late 1976 by Heckler & Koch. While our initial video does not go into detail on how the G11 operates, we will be covering this in later videos, this article will explain the action in more general terms.
Below are two diagrams showing the internal layout and major components of the G11 from a March 1982 draft of the ‘Rifle, 4.92mm, ACR’ armourer’s manual (source). It shows the major assembly groups and also a component list for the breech assembly.
From the diagram we can see the various action parts which feed the projectile into the breech, lock the action and ignite the round. We can also see the counter-recoil system beneath the barrel.
The G11 used a counter-recoil buffer mechanism to allow high rates of burst fire. When firing three round bursts the weapon send the rounds downrange at a rate of ~2,000 rounds per minute, only when the last round has left the barrel does the barrel and action begin to recoil inside the stock along a central guide. When in sustained fire the rate of fire is closer to ~460 per minute.
The buffer spring below the barrel is compressed as the recoiling barrel and breech assembly moves. In sustained fire the buffer spring is partially compressed with each round, but in burst fire the buffer is compressed to its maximum hitting before the buffer housing (which is when recoil from the burst is felt by the operator), this is described as having the barrel and breech assembly ‘float’.
To ready the weapon to fire a magazine was loaded into the magazine channel on top of the G11, a magazine dust door, which automatically closed when unloaded, was depressed as the magazine was pushed home. The cocking handle on the left side of the butt was then actuated. The operator rotated the handle 360-degrees counter-clockwise until the weapon was cocked (essentially like winding a clock). The same process will eject any rounds left in the chamber once the magazine has been removed.
Gas tapped from the barrel cycles the cylinder drive system with gas pushing a piston back to act on a series of gears which rotated the rotary breech from horizontal to vertical to allow a new cartridge to drop into the breech. There was a vent for high pressure gas underneath the butt stock this prevented pressure build up and mitigated some of the thermal build up.
The G11 K1 was tested by the German Army in the late 1980s with adoption planned for the early 1990s. Heckler & Koch continued to develop the G11, entering the G11 K2 into the US Army’s Advanced Combat Rifle (ACR) trials alongside entries from Steyr, AAI and Colt [all of which we will examine in upcoming videos]. However, the fall of the Berlin Wall in 1989 and the collapse of the Soviet Union in 1991 meant that West Germany no longer had the huge amount of funds needed to field the G11. At the same time the ACR program ended inconclusively and the G11 project was finally abandoned.
The extreme complexity of the design, the inadequacy of the weapon’s ergonomics and its inevitably high production cost casts doubt on whether the G11 would ever have seriously been considered for widespread adoption. Regardless of this the G11 is a fascinating footnote in small arms history representing a false start along a technological avenue which, with the Lightweight Small Arms Technologies (LSAT) program, may still prove fruitful. Heckler & Koch and Dynamit-Nobel’s ambitious design marks one of very few serious and potentially successful attempts engineers to overcome the plateau that firearms technology is currently stuck on.