Heckler & Koch G11
Encyclopedia
The Heckler & Koch G11 is a non-production prototype assault rifle
developed during the late 1960s, 1970s and 1980s by Gesellschaft für Hülsenlose Gewehrsysteme (GSHG) (German
for "Corporation for Caseless Rifle Systems"), a conglomeration of companies headed by firearm
manufacturer Heckler & Koch
(mechanical engineering and weapon design), Dynamit Nobel (propellant composition and projectile design), and Hensoldt Wetzlar (target identification and optic systems). The rifle is noted for its use of caseless ammunition
.
It was primarily a project of West Germany
, though it was also of significance to the other NATO countries as well. In particular, versions of the G11 were included in the U.S. Advanced Combat Rifle
program.
round used in assault rifle
s. The round also has similar ballistics
to a 5.56 mm round, but the 4.73 mm is much less likely to tumble when hitting or penetrating a target, and thus not as lethal. It is not clear to what extent the round would fragment, which could also make it more lethal. (See terminal ballistics
)
The design principle was to increase target hit probability by firing high rate multi-round bursts (salvos). Tests have been run using a prototype shotgun test-bed called CAWS to see whether a single-shot, multi-projectile system could achieve the range and hit probability requirements. The results indicated that the use of serially fired projectiles at a high rate of fire would achieve a tight shotgun-like pattern with rifle-like accuracy up to the required range.
The weapon itself has three firing modes: semi-auto, full-auto at 460 rounds per minute, and three-round burst at over 2000 cyclic rounds per minute, which is approximately 36 rounds per second. The loading and feed mechanism is physically very complicated but exceptionally fast and reliable. Rounds are fed into the weapon from a magazine that lies above and parallel with the barrel. The rounds are oriented vertically (at 90 degrees to the bore) and are fed downwards into the rotary chamber so that they can be rotated 90 degrees for firing. The firing cycle process is roughly:
A conventional assault rifle has approximately eight steps in its cycle:
Because the G11 uses caseless ammunition there are no extraction and ejection steps. Even though the rotary chamber doesn't, in the true sense of the word, lock up, the fact that it has to rotate in and out of alignment with the barrel, the G11 can be considered to have a lock/unlock phase. If a round fails to fire or the weapon is being used with training rounds, the rifle can be manually unloaded by twisting the cocking handle counterclockwise. This pushes the failed/training round out an emergency ejection port on the bottom of the rifle and loads the next round.
The recoil in the three-round burst is not felt by the weapon's user until after the third round has left the chamber. This is accomplished by having the barrel and feeding mechanism "float" within the rifle casing. When the rounds are fired, the barrel, magazine, chamber and operating mechanism recoils back against recoil springs several inches. Only when it strikes the buffer at the back of the rifle does the user feel the recoil. During the rearward travel of the internal mechanism the rifle loads and fires 3 rounds. When the barrel and mechanism reaches the rearmost point in its travel, the recoil springs push it forward back into its normal forward position. When firing in semi-auto and full-auto modes, the rifle only loads and fires one round per movement of the internal mechanism. Fully automatic fire is reduced to around 550 rounds per minute.
The internal workings of the rifle were rather complex compared to those of some earlier designs, with the guts being compared to the inside of a compact clock. The number of hours of maintenance required for the G11 as compared to other designs is not clear, especially since the impact of the powder used in the caseless ammo remains unknown. Designers claimed that because there was no ejection cycle the internal mechanisms would have little chance to get exposed to external dust, dirt and sand and this would supposedly reduce the need for cleaning.
There were reports that due to the high tolerances required to seal off the front and rear chamber openings the expected life of the contacting parts was around 6000 rounds before maintenance was required.
Premature ignition of ammunition from heat in the chamber, known as cook-off
, was a major problem with early prototypes of the G11 where synthetically bound nitrocellulose
, formed into blocks, was used. Normally, when a bullet is fed into a chamber
its case insulates the propellant from igniting until its impact-sensitive primer
is struck by a firing pin
or striker. The case aids in insulating the propellant from the heat of the chamber and it takes time for the temperature to rise sufficiently, inside a chambered round, to ignite the propellant. In addition, extracting a hot case removes heat from the system. As a result of doing away with traditional cases, the G11 became a safety hazard and had to be withdrawn from the 1979 NATO trials. The high rate of fire and lack of cartridge cases made cooking-off a significant problem.
To solve this, Heckler and Koch formed a partnership with Dynamit Nobel who redesigned the cartridge to use a new High Ignition Temperature Propellant (HITP). The cook-off problem was reduced, by using a denatured hexogen propellant with a special binder and coating for the ammunition that increased the spontaneous ignition temperature to 100 °C (180 °F) above that of standard, nitrocellulose
propellant.
An interesting feature of the new round was its unconventional shape. Most cartridge casings are cylindrical
; however the redesigned cartridge was molded into a squared, box-like shape. This allowed the 50-cartridge magazine to carry the maximum amount of propellant in a minimum of space, since the wasted spaces between rounds that accompanies the use of cylindrical cartridges was eliminated.
The issue of heat removal from caseless firing weapons as well as methods of igniting them continues to be researched by other companies. An alternative route was taken by the Austrian company, Voere
, which developed a caseless round for the Voere VEC-91
that was electrically fired
. This technique makes it possible to greatly increase the ignition temperature of the ammunition, while maintaining the ability to fire it. This would increase the maximum rate and duration a gun could fire at before cooking off rounds, but the VEC-91 never took advantage of this, since it was a bolt-action
rifle. Currently, the only weapon that electrically fires caseless ammunition automatically is Metal Storm.
and other NATO partners. Although the weapon was a technical success, it never entered full production due to the political changes of German reunification
and lack of procurement contract. Only 1000 units were ever produced, some of which made their way into the hands of the Bundeswehr
.
By 2004, the technology developed for the G11 was licensed for the Lightweight Small Arms Technologies
project, the current project of which is a light machine gun
prototype for the US Army. The design is intended to be able to proceed with either a cased cartridge using a composite case or a caseless ammunition design developed from the G11. Both ammunition designs are telescoped ammunition
like that used by the G11, however the current ammunition design has a plastic case in contrast to the fully caseless G11 ammunition. The design, like the G11, uses a rotating bolt, but rotating about the longitudinal axis of the weapon.
Ultimately, the German armed forces replaced the G3 with the G36.
Assault rifle
An assault rifle is a selective fire rifle that uses an intermediate cartridge and a detachable magazine. Assault rifles are the standard infantry weapons in most modern armies...
developed during the late 1960s, 1970s and 1980s by Gesellschaft für Hülsenlose Gewehrsysteme (GSHG) (German
German language
German is a West Germanic language, related to and classified alongside English and Dutch. With an estimated 90 – 98 million native speakers, German is one of the world's major languages and is the most widely-spoken first language in the European Union....
for "Corporation for Caseless Rifle Systems"), a conglomeration of companies headed by firearm
Gun
A gun is a muzzle or breech-loaded projectile-firing weapon. There are various definitions depending on the nation and branch of service. A "gun" may be distinguished from other firearms in being a crew-served weapon such as a howitzer or mortar, as opposed to a small arm like a rifle or pistol,...
manufacturer Heckler & Koch
Heckler & Koch
Heckler & Koch GmbH is a German defense manufacturing company that produces various small arms. Some of their products include the SA80, MP5 submachine gun, G3 automatic rifle, the G36 assault rifle, the HK 416, the MP7 personal defense weapon, the USP series of handguns, and the high-precision...
(mechanical engineering and weapon design), Dynamit Nobel (propellant composition and projectile design), and Hensoldt Wetzlar (target identification and optic systems). The rifle is noted for its use of caseless ammunition
Caseless ammunition
Caseless ammunition is a type of small arms ammunition that eliminates the cartridge case that typically holds the primer, propellant, and projectile together as a unit...
.
It was primarily a project of West Germany
West Germany
West Germany is the common English, but not official, name for the Federal Republic of Germany or FRG in the period between its creation in May 1949 to German reunification on 3 October 1990....
, though it was also of significance to the other NATO countries as well. In particular, versions of the G11 were included in the U.S. Advanced Combat Rifle
Advanced Combat Rifle
The Advanced Combat Rifle was a United States Army program to find a replacement for the M16 assault rifle. The program's total cost is approximately US$300 million...
program.
Design details
The weapon uses 4.73x33 mm caseless ammunition, with the propellant shaped into square blocks. The ammunition has also been designated as 4.92 mm because for the HK G11 ACR, a variant developed for US Military trials, the US convention of groove to groove measurements of the bore was employed, rather than land-land. The projectile is 4.93 mm in diameter with a case length of 33mm, the US case length measurement is 34mm since for the ACR trials the chamber length, not the actual case length was used. The 4.73 mm round is half the weight and 40% the size by volume of the 5.56x45mm NATO5.56x45mm NATO
5.56×45mm NATO is a rifle cartridge developed in the United States and originally chambered in the M16 rifle. Under STANAG 4172, it is a standard cartridge for NATO forces as well as many non-NATO countries. It is derived from, but not identical to, the .223 Remington cartridge...
round used in assault rifle
Assault rifle
An assault rifle is a selective fire rifle that uses an intermediate cartridge and a detachable magazine. Assault rifles are the standard infantry weapons in most modern armies...
s. The round also has similar ballistics
Ballistics
Ballistics is the science of mechanics that deals with the flight, behavior, and effects of projectiles, especially bullets, gravity bombs, rockets, or the like; the science or art of designing and accelerating projectiles so as to achieve a desired performance.A ballistic body is a body which is...
to a 5.56 mm round, but the 4.73 mm is much less likely to tumble when hitting or penetrating a target, and thus not as lethal. It is not clear to what extent the round would fragment, which could also make it more lethal. (See terminal ballistics
Terminal ballistics
Terminal ballistics, a sub-field of ballistics, is the study of the behavior of a projectile when it hits its target. It is often referred to as stopping power when dealing with human or other living targets. Terminal ballistics is relevant both for small caliber projectiles as well as for large...
)
The design principle was to increase target hit probability by firing high rate multi-round bursts (salvos). Tests have been run using a prototype shotgun test-bed called CAWS to see whether a single-shot, multi-projectile system could achieve the range and hit probability requirements. The results indicated that the use of serially fired projectiles at a high rate of fire would achieve a tight shotgun-like pattern with rifle-like accuracy up to the required range.
The weapon itself has three firing modes: semi-auto, full-auto at 460 rounds per minute, and three-round burst at over 2000 cyclic rounds per minute, which is approximately 36 rounds per second. The loading and feed mechanism is physically very complicated but exceptionally fast and reliable. Rounds are fed into the weapon from a magazine that lies above and parallel with the barrel. The rounds are oriented vertically (at 90 degrees to the bore) and are fed downwards into the rotary chamber so that they can be rotated 90 degrees for firing. The firing cycle process is roughly:
- As the cocking handle on the side is rotated clockwise by the weapon operator:
- A round is dropped into the revolving chamber vertically (a loading piston assists this process).
- The chamber rotates 90° until it is lined up with the barrel. This completes the chambering of the round and cocking of the firing pin.
- When the trigger is pulled, a firing pin ignites the primer, which then ignites a powder booster charge that pushes the bullet into the barrel. The solid block of propellant is broken up to increase the ignition surface area and ignites, accelerating the bullet out of the barrel.
- As the projectile is accelerating up the barrel, recoil forces drive the barrel, magazine, chamber and operating mechanism rearwards within the weapon, dissipating energy for single shot and fully automatic modes but allowing burst mode to deliver three projectiles downrange before buffering occurs.
- Gas tapped off from the barrel rotates the chamber and actuates the loading mechanism then rotating the chamber back to the vertical original position until it is lined up with the feed mechanism and the process repeats.
A conventional assault rifle has approximately eight steps in its cycle:
- Battery: bolt group pushes round from magazine into chamber.
- Lockup: bolt or bolt carrier locks with the barrel extension or receiver.
- Firing: firing pin or striker impacts primer igniting the main propellant charge.
- Unlocking: either through gas, recoil or blow-back operation, the working parts unlock from the barrel extension or receiver.
- Extraction: spent case is extracted and withdrawn from the chamber.
- Ejection: the spent case is thrown clear of the weapon either via a bolt face ejector or from a fixed or semi-fixed ejector.
- Firing mechanism reset: as part of the rearward reciprocation of the working parts, the firing mechanism is reset.
- Buffering: working parts finally strike the buffer and halt. Recoil spring(s) are fully compressed and begin to drive the working parts forward into battery.
Because the G11 uses caseless ammunition there are no extraction and ejection steps. Even though the rotary chamber doesn't, in the true sense of the word, lock up, the fact that it has to rotate in and out of alignment with the barrel, the G11 can be considered to have a lock/unlock phase. If a round fails to fire or the weapon is being used with training rounds, the rifle can be manually unloaded by twisting the cocking handle counterclockwise. This pushes the failed/training round out an emergency ejection port on the bottom of the rifle and loads the next round.
The recoil in the three-round burst is not felt by the weapon's user until after the third round has left the chamber. This is accomplished by having the barrel and feeding mechanism "float" within the rifle casing. When the rounds are fired, the barrel, magazine, chamber and operating mechanism recoils back against recoil springs several inches. Only when it strikes the buffer at the back of the rifle does the user feel the recoil. During the rearward travel of the internal mechanism the rifle loads and fires 3 rounds. When the barrel and mechanism reaches the rearmost point in its travel, the recoil springs push it forward back into its normal forward position. When firing in semi-auto and full-auto modes, the rifle only loads and fires one round per movement of the internal mechanism. Fully automatic fire is reduced to around 550 rounds per minute.
The internal workings of the rifle were rather complex compared to those of some earlier designs, with the guts being compared to the inside of a compact clock. The number of hours of maintenance required for the G11 as compared to other designs is not clear, especially since the impact of the powder used in the caseless ammo remains unknown. Designers claimed that because there was no ejection cycle the internal mechanisms would have little chance to get exposed to external dust, dirt and sand and this would supposedly reduce the need for cleaning.
There were reports that due to the high tolerances required to seal off the front and rear chamber openings the expected life of the contacting parts was around 6000 rounds before maintenance was required.
Ammunition cook-off and shape
Cooking off
Cooking off refers to ammunition exploding prematurely due to heat in the surrounding environment. It can also refer to a technique used when throwing grenades to achieve a controlled, predictable explosion....
, was a major problem with early prototypes of the G11 where synthetically bound nitrocellulose
Nitrocellulose
Nitrocellulose is a highly flammable compound formed by nitrating cellulose through exposure to nitric acid or another powerful nitrating agent. When used as a propellant or low-order explosive, it is also known as guncotton...
, formed into blocks, was used. Normally, when a bullet is fed into a chamber
Chamber (weaponry)
In firearms, the chamber is that portion of the barrel or firing cylinder in which the cartridge is inserted prior to being fired. Rifles and pistols generally have a single chamber in their barrels, while revolvers have multiple chambers in their cylinders and no chamber in their barrel...
its case insulates the propellant from igniting until its impact-sensitive primer
Percussion cap
The percussion cap, introduced around 1830, was the crucial invention that enabled muzzleloading firearms to fire reliably in any weather.Before this development, firearms used flintlock ignition systems which produced flint-on-steel sparks to ignite a pan of priming powder and thereby fire the...
is struck by a firing pin
Firing pin
A firing pin or striker is part of the firing mechanism used in a firearm or explosive device e.g. an M14 landmine or bomb fuze. Firing pins may take many forms, though the types used in landmines, bombs, grenade fuzes or other single-use devices generally have a sharpened point...
or striker. The case aids in insulating the propellant from the heat of the chamber and it takes time for the temperature to rise sufficiently, inside a chambered round, to ignite the propellant. In addition, extracting a hot case removes heat from the system. As a result of doing away with traditional cases, the G11 became a safety hazard and had to be withdrawn from the 1979 NATO trials. The high rate of fire and lack of cartridge cases made cooking-off a significant problem.
To solve this, Heckler and Koch formed a partnership with Dynamit Nobel who redesigned the cartridge to use a new High Ignition Temperature Propellant (HITP). The cook-off problem was reduced, by using a denatured hexogen propellant with a special binder and coating for the ammunition that increased the spontaneous ignition temperature to 100 °C (180 °F) above that of standard, nitrocellulose
Nitrocellulose
Nitrocellulose is a highly flammable compound formed by nitrating cellulose through exposure to nitric acid or another powerful nitrating agent. When used as a propellant or low-order explosive, it is also known as guncotton...
propellant.
An interesting feature of the new round was its unconventional shape. Most cartridge casings are cylindrical
Cylinder (geometry)
A cylinder is one of the most basic curvilinear geometric shapes, the surface formed by the points at a fixed distance from a given line segment, the axis of the cylinder. The solid enclosed by this surface and by two planes perpendicular to the axis is also called a cylinder...
; however the redesigned cartridge was molded into a squared, box-like shape. This allowed the 50-cartridge magazine to carry the maximum amount of propellant in a minimum of space, since the wasted spaces between rounds that accompanies the use of cylindrical cartridges was eliminated.
The issue of heat removal from caseless firing weapons as well as methods of igniting them continues to be researched by other companies. An alternative route was taken by the Austrian company, Voere
Voere
Voere is an Austrian gunmaker best known for its VEC-91 bolt-action rifle using caseless ammunition. The origins of the company date back to the 1948 establishment of the metal-working company Koma in West Germany. Originally producing bicycle tire pumps, the company branched out into the...
, which developed a caseless round for the Voere VEC-91
Voere VEC-91
The Voere VEC-91, made by Voere, is the first commercial sporting rifle to combine caseless ammunition and electronic firing. Depending upon its chambering, it fires a 5.7 mm or 6 mm projectile at speeds of up to 930 meters per second . When chambered for 5.7 mm it has a 5 round magazine, and it...
that was electrically fired
Electronic firing
Electronic firing refers to the use of an electric current to fire a cartridge, instead of a percussion cap.In modern firearm designs, a firing pin and percussion cap are used to ignite the propellant in the cartridge and propels the bullet forward...
. This technique makes it possible to greatly increase the ignition temperature of the ammunition, while maintaining the ability to fire it. This would increase the maximum rate and duration a gun could fire at before cooking off rounds, but the VEC-91 never took advantage of this, since it was a bolt-action
Bolt-action
Bolt action is a type of firearm action in which the weapon's bolt is operated manually by the opening and closing of the breech with a small handle, most commonly placed on the right-hand side of the weapon...
rifle. Currently, the only weapon that electrically fires caseless ammunition automatically is Metal Storm.
Future
In 1990, H&K finished the development of the G11, intended for the BundeswehrBundeswehr
The Bundeswehr consists of the unified armed forces of Germany and their civil administration and procurement authorities...
and other NATO partners. Although the weapon was a technical success, it never entered full production due to the political changes of German reunification
German reunification
German reunification was the process in 1990 in which the German Democratic Republic joined the Federal Republic of Germany , and when Berlin reunited into a single city, as provided by its then Grundgesetz constitution Article 23. The start of this process is commonly referred by Germans as die...
and lack of procurement contract. Only 1000 units were ever produced, some of which made their way into the hands of the Bundeswehr
Bundeswehr
The Bundeswehr consists of the unified armed forces of Germany and their civil administration and procurement authorities...
.
By 2004, the technology developed for the G11 was licensed for the Lightweight Small Arms Technologies
Lightweight Small Arms Technologies
The Lightweight Small Arms Technologies program is funded by the U.S. Joint Service Small Arms Program, with the goal of significantly reducing the weight of small arms and their ammunition...
project, the current project of which is a light machine gun
Light machine gun
A light machine gun is a machine gun designed to be employed by an individual soldier, with or without an assistant, as an infantry support weapon. Light machine guns are often used as squad automatic weapons.-Characteristics:...
prototype for the US Army. The design is intended to be able to proceed with either a cased cartridge using a composite case or a caseless ammunition design developed from the G11. Both ammunition designs are telescoped ammunition
Telescoped ammunition
Telescoped ammunition is an ammunition design in which the projectile is partly or completely enveloped by the propellant. Examples include ammunition for both hand weapons and artillery.-External links:*http://www.veritay.com/defense/def_ammo.htm...
like that used by the G11, however the current ammunition design has a plastic case in contrast to the fully caseless G11 ammunition. The design, like the G11, uses a rotating bolt, but rotating about the longitudinal axis of the weapon.
Ultimately, the German armed forces replaced the G3 with the G36.
See also
- Armtech C30RArmtech C30RThe Armtech C30R was an assault rifle concept using 5.56mm similar to the H&K G11..-See also:*Heckler & Koch G11*Gyrojet*Steyr ACR...
- Gerasimenko VAG-73Gerasimenko VAG-73The Gerasimenko VAG-73 is a Russian pistol capable of firing caseless bullets from a 48 round grip-inserted magazine....
- Metal StormMetal StormMetal Storm Limited is a Brisbane, Australia based research and development company that specializes in electronically initiated superposed load weapons technology and owns the proprietary rights to the electronic ballistics technology invented by J. Mike O'Dwyer. Metal Storm represents both the...
- Voere VEC-91Voere VEC-91The Voere VEC-91, made by Voere, is the first commercial sporting rifle to combine caseless ammunition and electronic firing. Depending upon its chambering, it fires a 5.7 mm or 6 mm projectile at speeds of up to 930 meters per second . When chambered for 5.7 mm it has a 5 round magazine, and it...
- Steyr ACRSteyr ACRThe Steyr ACR was a prototype flechette-firing assault rifle built for the US Army's Advanced Combat Rifle program of 1989/90. Although the Steyr design proved effective, as did most of the weapons submitted, the entire ACR program ended with none of the entrants achieving performance 100% better...
- Benelli CB M2Benelli CB M2The Benelli CB-M2 was a unique submachine gun of Italian conception resulting from a joint venture between Benelli and Fiocchi Munizioni, the biggest ammunition manufacturer of Italy. The weapon itself was unremarkable, and operated by a simple blowback system, which is very common for submachine...