High-Tech: Caseless Ammunition and the H&K G11, MP11, and MG11

The streamlined plastic butt of an H&K didn’t exactly hurt, either, and Rydell could see one peeking out of Svobodov’s open flak vest. Couldn’t remember the model number … Shot that caseless ammo looked like wax crayons, plastic propellant molded around alloy flechettes like big nails … Orlovsky was pulling out his H&K … Nothing in the world ever sounded like caseless ammunition, on full-auto, out of a floating breech. It wasn’t the sound of a machine gun, but a kind of ear-shattering, extended whoop.

– William Gibson, Virtual Light (set in 2005)

Ever since the 1980s and for much of the 1990s we have been promised caseless ammunition and the advanced weapons firing them. If not now, then very soon. Science-fiction authors and designers of games like Cyberpunk 2020, Shadowrun, and Twilight: 2000 were positive that we would see them in the immediate future. Even industry authorities were taken in by the hype. Master Gunner Ian Hogg claimed in Jane’s Infantry Weapons, 17th Edition (1991) that the famous H&K G11 assault rifle and its 4.73×33mm caseless ammunition were in production and had already been issued to West German “special forces” in 1990 ‒ when in fact the rifle actually never entered production and furthermore the Bundeswehr had no such forces at the time, unless one counts the tiny Kampfschwimmer (combat diver) and Fernspäher (long range recon) units. Similarly, Sergeant Kevin Dockery erroneously reported in his appropriately titled book Future Weapons (2007) that at least 1,000 G11 rifles had been produced …


In reality, the Bundeswehr did certify the G11 assault rifle and its 4.73×33mm caseless ammunition for adoption in early 1990, envisioning an initial first batch production of no less than 224,000 weapons starting in 1991. However, the project was halted in late 1990, the year of German reunification, died with the end of the US Army’s Advanced Combat Rifle (ACR) programme in 1992, and was finally cancelled by the Bundeswehr in 1993. H&K had produced just 265 G11 rifles, including no less than 14 prototype iterations and the three pre-production variants made since 1972. The overall number includes the 21 pre-production rifles that were supplied to the US Army. No more were made and the weapon was never issued to anyone.


So what happened? Where are the G11, the MP11, the MG11, not to speak of follow-up products by competitors like the Armat M41A pulse rifle?

Caseless Ammunition

The advantages of caseless ammunition are many. Caseless telescoped rifle cartridges have only about 50% of the weight per shot of comparable cased cartridges (GURPS High-Tech, pp. 164-165) and take up only about 60-70% of the volume, decreasing the burden on the shooter and logistics system and increasing the potential magazine capacity. Caseless cartridges that are telescoped, that is entirely envelope the projectile, have a shorter overall cartridge length which allows a reduction of the weapon receiver length and the depth of the ammunition magazine. A caseless weapon can dispense with the extraction and ejection process of the spent cartridge case, which is a major source of malfunctions in conventional firearms. It also means the action can be kept closed, preventing entry of foreign material that can likewise lead to malfunctions. This potentially makes the weapon very reliable. Deleting the extraction and ejection phase allows for much higher theoretical cyclic rates, well over 2,000 shots per minute depending on the specific action used. Since there is no ejection, the action can stay closed during firing, which permits use of a floating mechanism in which the barrel, magazine, and action slide backwards in the hollow stock while firing. Together with the high cyclic rate, this means that when provided with a controlled burst mechanism, the weapon can fire a few shots ‒ typically three ‒ so fast that the shooter does not feel the recoil impulse until after the last shot has left the barrel, improving hit probability. A caseless long arm can also easier be made ambidextrous, even in bullpup configurations. Finally, there are no spent cases cluttering up the place, a minor but possibly important point in a number of scenarios such as when used in vehicles, especially air- or spacecraft, at crime scenes, etc.


Unfortunately, caseless ammunition also has downsides. A cartridge case actually performs several critical functions. The main issue is obturation, the sealing of the chamber. The cartridge case safely contains the explosion of the propellant and channels it in one and only one direction, the barrel. Without a case, the chamber itself has to be sealed during firing, which is rather complex considering that at some point the cartridge needs to be inserted into it in some way. The case also acts as a heat sink, taking some of the explosion’s heat with it as it is ejected out of the weapon. A weapon that becomes too hot can fail mechanically or even unintentionally set off a chambered cartridge (“cook off”). Other important functions of the case include protection against the elements and a way of easily removing the cartridge in case the chambered round will not go off or is in fact to be ejected manually for administrative or safety reasons. Caseless cartridges provide no obturation, leave all the heat in the weapon, and need to be sufficiently robust to withstand the elements and rough handling. A less serious problem is that caseless cartridges cannot be handloaded, meaning tinkered with for improved performance. While this might be a problem for snipers and target shooters, it is really nothing to worry about for ordinary police, military, or civilian users who only use commercial or officially-provided ammunition anyway. Soldiers just do not handload their ammunition, and neither do cops.

Some critics of caseless ammunition claim that it is a failed concept. These included Jim Schatz, who was an employee of H&K between 1986 to 2006 with direct involvement in the ACR trial as the military programmes manager and US contract developer. In 2012, Schatz presented at paper at the NDIA Joint Armaments Conference that doubted the future of caseless weapons, pointing out all the problems mentioned above. Schatz was an industry heavyweight and intimately familiar with the G11. Was he right and caseless ammunition is not to be?

By all accounts, including Schatz’s, the “cook off” problem had been solved in Dynamit-Nobel’s 4.73×33mm caseless cartridge by replacing conventional propellant with a High Ignition Temperature Propellant (HITP) consisting of a nitromine (HMX/RDX) explosive that has a considerably higher cook-off temperature. In fact, unlike conventional propellant, HITP is safer since it cannot detonate accidentally and will deflagrate instead. While HITP is currently more expensive than conventional propellant, it is likely that the cost increase would be completely outweighed in full production by the cost savings of deleting the expensive brass case. The importance of the case as a heat sink is not as big as is commonly believed, since metallic cases take only about 5-10% of the generated heat with them as they are ejected. The 4.73×33mm caseless cartridges are quite waterproof, even surviving prolonged immersion in water. The issue of physically handling the cartridges was addressed by supplying the ammunition in sealed plastic reloading units (containing 10 or 15 cartridges apiece), protecting the cartridge between the time it was produced in the factory and the time it was inserted into the magazine. The caseless cartridges also turned out to be reasonably robust even if handled unprotected. The ACR summary called it “extremely hard but not friable.” The main issue, the problem of obturation, was supposedly also solved with the G11. Schatz and others were not quite as confident about this, predicting catastrophic chamber explosions that would destroy the weapon. However, this seems to have been primarily a theoretical problem, as such a catastrophic sealing failure did not occur during the 90,000-round ACR trial.

What remained were problems when a chambered cartridge had to be removed from the weapon manually. While rare, broken or chipped cartridges could jam the weapon and proved difficult and sometimes even impossible to clear in the field. Undoubtedly the G11’s complicated mechanism and the nature of the caseless cartridges created new and hitherto unheard-of jams and failures, some of which were impossible to remedy by troops and required an armourer and workshop. However, conventional cased rifles also sometimes develop problems that just cannot be solved by the shooter and require an armourer’s attention. More importantly, the G11 was actually very reliable overall, much more so than comparable conventional weapons. The likelihood of these complicated jams thus was extremely small. You would not want to be the chap it happened to, but again, catastrophes do happen with conventional arms all the time as well and nobody considers abandoning them outright.

Another issue to take into account is that at least some of the potential problems of caseless firearms identified with the G11 are really not the result of using caseless ammunition, but the particular design of the G11. The infamously complex clockwork action of the G11, which prevented solving some jams below the armourer-level, was mainly the result of wanting to achieve the 3-round controlled burst, not because it was designed to fire caseless ammunition. In other words, caseless ammunition used in weapons with less complex actions would probably fare better than the G11, which, it bears keeping in mind, did pass all technological requirements by the Bundeswehr and was adopted.

Ironically, the programme summary of the US Army’s ACR showed that, while the tested advanced designs including the G11 all worked, the basic premise, the increased hit probability by firing a 3-round controlled burst, was simply not correct:

No rifles showed an increase in probabilty of hit over the M16A2 rifle under the stressed conditions of the test. This is primarily because the soldiers performed better than expected; meaning their aiming errors were smaller than anticipated. Therefore, the salvo burst sizes were too large to effectively increase the probability of a least one projectile hitting the target. Another contributing factor is that the burst size actually obtained from the weapons was somewhat greater than that originally requested.

In other words, a caseless rifle without the controlled burst mechanism might be more successful.

Like all technological concepts, caseless ammunition and guns would undoubtedly have been improved once they were actually produced and used in volume, just like other technological leapfrogs such as the metallic cartridge, smokeless ammunition, the machine gun, the assault rifle, the polymer-frame handgun, etc. As an example, most of the remaining handling issues of the 4.73×33mm caseless telescoped cartridge were the result of its square profile body, which suffers from more vulnerable stress points. More recent caseless developments therefore employ round profile bodies, which are more robust.

A final problem that was never addressed since the G11 family never actually saw combat are doubts over the lethality of its small-calibre bullet. Unfortunately, given the occasional performance issues of larger calibres like the 5.56×45mm NATO, it is uncertain whether the even smaller 4.73×33mm cartridge would have been ultimately successful.

Caseless cartridges are perhaps more promising for heavy vehicular weapons, especially aircraft, since these profit even more from weight and space savings and additionally from the need to deal with the ejected cases. The increased reliability would also be extremely welcome in an aircraft, while the required armourer attention would actually be standard anyway. The prototyped Rheinmetall RMK35-1 recoilless autocannon chambering the 35×350mm caseless cartridge is a neat example … it might be the one used on the Canadair CL-227 drone in Bruce Sterling’s cyberpunk novel Islands in the Net (set in 2023).


H&K G11, 4.73×33mm Dynamit-Nobel (Germany, 1991-)

Continuously developed from 1972, the Gewehr 11 (“rifle model 11” meaning the first rifle in its calibre group) was intended to replace the H&K G3A3 and G3A4 (High-Tech, p. 116, and Investigator Weapons 2: Modern Day, pp. 104-106) and IMI MP2A1 (the Uzi, High-Tech, pp. 125-126, and Investigator Weapons 2, pp. 161-163) with the West German Bundeswehr from 1990/1991. The G11 was designed by a team led by Tilo Möller.

It is chambered for 4.73×33mm caseless telescoped ammunition (In the USA, the cartridge is called the 4.92×34mm, but this just reflects a different way of measuring; the rounds are identical.) This fires a 3.25-g spitzer bullet at 930 m/s. The whole cartridge weighs only 5.3 g (WPS 0.012 lb.).

In 3-round controlled burst mode, a cyclic rate of well over 2,000 shots per minute is achieved. On full-automatic, it fires at around 460 shots per minute. On single shot or full-automatic, the G11 has mild recoil, but the combined force of three shots in burst mode is surprisingly violent. The G11 is almost completely ambidextrous.

The pre-production G11K1 has a 54-cm barrel, is 75 cm long, and weighs 4.15 kg (Wt. 9.13 lbs.) loaded with 50 rounds. (The numbered K suffix stands for Konstruktionsstand or “engineering version” ‒ the final version(s) would have lost it or received an A suffix for Ausführung or “pattern.”) The magazine lies horizontally on top of the barrel and feeds the rectangular cartridges downwards into the rotary chamber, which rotates 90° to align the chamber with the barrel. The pre-production G11K2 used a 45-round magazine and adds rails on either side of the magazine in use to accept spare magazines. (There is some evidence that the G11K1 and ACR eventually also used the 45-round magazine, since although the ACR selector is clearly marked -50 and the ACR manual describes the 50-rounder, the ACR summary speaks of the 45-rounder.) The reason for this feature is the length (45 cm in the 45-round pattern) and unwieldiness of the magazines, which cannot be carried easily in load-bearing equipment. In action, the G11K2 was intended to carry two full magazines ‒ one loaded and one on the right rail. When the loaded magazine runs empty, it is placed on the left rail, and the spare from the right rail is inserted. This allows the magazines to always stay with the weapon and not be placed on the ground. Of course, a third magazine could theoretically be carried as well, but this would make the reloading more awkward unless the magazines are considered disposable. Additional ammunition beyond the two magazines on the rifle is carried in compact 15-round reloading units rather than in magazines. On the G11K2, the detachable carrying handle includes a tritium-illuminated Swarovski 1-3.5× optical sight (+0/+1 Acc) that allows aiming with both eyes open (High-Tech, pp. 155-156, Investigator Weapons 2, p. 195). The G11K2 weighs 4.4 kg loaded with 45 rounds (Wt. 9.68 lbs.), 4.8 kg with one spare magazine stored on the right rail (Wt. 10.56 lbs.). An underbarrel attachment point can mount a 0.3-kg (Wt. 0.66 lbs.) bayonet with 17-cm blade (High-Tech, p. 197, Investigator Weapons 2, p. 200) or a targeting laser (High-Tech, pp. 156-157, and Investigator Weapons 2, pp. 197-198).

H&K proposed minor ergonomic improvements to create the pre-production G11K3, including a slimmer buttplate and a knuckle-protecting trigger guard for the entire shooting hand similar to the one on the Steyr AUG.

Only 265 G11 prototype and pre-production rifles were produced in all, only few of these conforming to the finished parameters. These included 27 G11K1 and six G11K2 pre-production samples for the Bundeswehr in 1989. Exactly 20 ACR rifles ‒ practically identical with the G11K1 ‒ were supplied in 1989 to the US Army for its ACR trials held in early 1990. The US Army also acquired a single G11K2.

Had the G11 actually entered full production service ‒ presumably along the lines of the G11K2 or G11K3 ‒ it would have undoubtedly seen some minor improvements and developments over the years. Accessory rails (High-Tech, p. 161) for optional sights, targeting lasers, etc. are almost guaranteed. It might have received a 40×46mmSR underbarrel grenade launcher not unlike the H&K L17A2 (High-Tech, p. 144) mounted under the H&K L85A2 bullpup assault rifle of the British, although German doctrine in the 1980s and indeed American tactics in the 2020s actually prefer a light stand-alone weapon along the lines of the H&K HK69A1 Granatpistole (High-Tech, p. 142, Investigator Weapons 2, p. 180) or the H&K HK169. A sound suppressor (High-Tech, pp. 158-159, Investigator Weapons 2, pp. 193-194) was already discussed in 1992.

TO USE, remove an empty magazine. Insert a new magazine from the front. Turn the cocking handle on the left side counter-clockwise through a full 360°. Set the fire selector to either the red 1 for single shots, red 3 for 3-round bursts, or red -45 (-50 on the G11K1/ACR) for full-automatic fire. This takes one combat round. The gun is now ready to fire. Rotate the selector to the white S (Sicher, or “safe”) to make safe. Trained shooters fire single shots; per the manual, the 3-round bursts are primarily intended for moving targets, and full-automatic bursts are only useful at short ranges and for suppression fire. The typical malfunction is a misfire or some related problem with the ammunition.

The G11K2/G11K3 comes with two 45-round magazines, each weighs 0.4 kg (0.88 lb.) filled. The crayon-like caseless cartridges are supplied from the factory in sealed 15-round reloading units, which weigh 0.11 kg (0.24 lb.) each. To fill a magazine, strip off the sealing foil, insert the magazine into the unit, and push the cartridges in. The standard round is the brownish DM11 full-metal jacket round, but there is also the red DM12 tracer round. The green DM10 shown in the photo above is a dummy/drill cartridge.

The carrying handle with the integral optic can be readily removed and replaced by a passive night vision sight like the 1.8-kg (4 lbs.) Zeiss Orion 80 4× image-intensifying sight (High-Tech, p. 156, Investigator Weapons 2, p. 196). The rechargeable battery lasts for 25 hours.

For GURPS stats, see High-Tech (p. 120).

In Call of Cthulhu, Seventh Edition, the G11 has excellent Malf compared to similar weapons. In 3-round controlled burst mode, it gets a bonus die. The tritium-illuminated 1× optical sight helps with “Shooting in Darkness” (Investigator Weapons 2, p. 23). When set for 3.5×, the sight doubles Base Range. The Zeiss Orion 80 4× image-intensifying sight doubles Base Range and allows shots in starlight (Investigator Weapons 2, p. 23).

Rifles Table

For an explanation of the statistics, see Investigator Weapons 2, pp. 47-51.

Make/Model/Calibre Skill Base Chance Damage Base Range ROF Capacity HP Malf Year Price Avail
H&K G11, 4.73×33mm Firearms (Rifle/Shotgun)* 25% 2D6+1 90 1(3), Burst 3, or 20 45+1 10 00 1992- $3,000

H&K MP11, 4.73×25mm Dynamit-Nobel (Germany, 1992)

The Maschinenpistole 11 is a personal defence weapon chambered for the 4.73×25mm caseless telescoped cartridge that is slightly shorter and less powerful than that used in the G11. The MP11 has a rising breech for simplified feed and a straight 20-round magazine that inserts into the grip. This fires a 2.75-g spitzer bullet at 585 m/s. The entire cartridge weighs 4 g (WPS 0.009 lb.). Unlike the G11, the breech does not “float” inside the receiver. The MP11 is not designed to fire 3-round controlled bursts, only normal full-automatic fire. The known mock-up design lacks accessories of any kind, but the perfected MP11 would undoubtedly feature a retractable stock (High-Tech, p. 160), folding foregrip (GURPS Tactical Shooting, p. 75), accessory rails, and optional extended 30-round and 40-round magazines (High-Tech, p. 155) just like the conventional H&K MP7A1 in 4.6×30mm (High-Tech, p. 126, Investigator Weapons 2, pp. 159-160), which actually looks a lot like it and undoubtedly was inspired by the MP11 design work.

TO USE, remove an empty magazine. Insert a new magazine into the grip. Rack the charge handle at the rear of the receiver. Set the fire selector to either the red bullet for single shots or four red bullets for full-automatic fire. This takes one combat round. The gun is now ready to fire. Rotate the selector to the white crossed-out bullet to make safe. Trained shooters fire single shots or short bursts of 3-5 shots. The typical malfunction is a misfire or some related problem with the ammunition.

For GURPS stats, see Pyramid #3/100 (p. 14).

In Call of Cthulhu, Seventh Edition, the MP11 has excellent Malf compared to similar weapons.

Submachine Guns Table

For an explanation of the statistics, see Investigator Weapons 2, pp. 47-51.

Make/Model/Calibre Skill Base Chance Damage Base Range ROF Capacity HP Malf Year Price Avail
H&K MP11, 4.73×25mm Firearms (Submachine Gun)* 25% 2D6 50 2(3) or 20 20/30/40+1 10 00 1992- $2,000


H&K MG11, 4.73×33mm Dynamit-Nobel (Germany, 1992)

The Maschinengewehr 11 (“machine gun model 11”)  was intended to partner with the G11 as a squad automatic weapon in the Bundeswehr from the mid-1990s, partially replacing the Rheinmetall MG3 general-purpose machine gun (High-Tech, p. 134, Investigator Weapons 2, pp. 171-172). The MG11 is chambered for the same 4.73×33mm caseless telescoped ammunition as the rifle. Unlike the G11, it does not have a rotary chamber, but instead uses a three-chamber revolver action like some aircraft autocannon. The three chambers allow for both a high cyclic rate of fire, as one chamber is firing a cartridge while at the same time the other two are in different stages of feeding one, and a higher sustained rate of fire, as the chambers divide the firing heat among them. On full-automatic, it fires at around 600 shots per minute. From the available data, it is unclear whether it can also fire 3-round controlled bursts, but it is likely since it also has a floating action. Its springless magazine, which is inserted from the rear, holds an astonishing 300 rounds. The MG11 is 90 cm long and weighs 7 kg loaded. Like the G11, it has a detachable carrying handle which includes a tritium-illuminated Swarovski 1-3.5× optical sight that allows aiming with both eyes open. Notably, the mockup lacks a bipod, but would probably have received one to improve its performance as a support weapon.

TO USE, break open the buttstock, insert an ammunition package, and close up again. Unfold the cocking handle under the barrel and rack backwards. Set the fire selector to either the red bullet for single shots, three red bullets for 3-round bursts, or seven red bullets for full-automatic fire. This takes one combat round. The gun is now ready to fire. Rotate the selector to the white crossed-out bullet to make safe. The typical malfunction is a misfire or some related problem with the ammunition.

In GURPS, the MG11 is Very Reliable and won’t malfunction unless lack of maintenance lowers Malf. (p. B407). The 3-round high-cyclic controlled bursts uses special rules (High-Tech, p. 83).

Machine Guns Table

See pp. B268-271 for an explanation of the statistics.

GUNS (MACHINE GUN) (DX-4 or most other Guns at ‑2)

TL Weapon Damage Acc Range Weight RoF Shots ST Bulk Rcl Cost LC
8 H&K MG11, 4.73×33mm 4d+2 pi 5+1 550/4,150 15.4/4 9#/10 300(5) 10B† -6 2 $4,000 2

In Call of Cthulhu, Seventh Edition, the MG11 has excellent Malf compared to similar weapons. In 3-round controlled burst mode, it gets a bonus die. The sight works like on the G11.

Machine Guns Table

For an explanation of the statistics, see Investigator Weapons 2, pp. 47-51.

Make/Model/Calibre Skill Base Chance Damage Base Range ROF Capacity HP Malf Year Price Avail
H&K MG11, 4.73×33mm Firearms (Machine Gun)* 15% 2D6+1 90 1(3), Burst 3, or 20 300 10 00 1992- $4,000