Grenade Launchers: The Spigots.

“Rifle grenades are regarded as the rifleman’s most reliable weapon against tanks, pill boxes, and exposed enemy personnel. At first, they may seem to be too small to d much damage, but their power is far greater than appearances would lead us to believe.”

Guidebook for Marines, Chapter 20, p.257 1951

Spigot-launched rifle grenades are a little bit better known than cup and rod grenades. Very occasionally they appear in movies. The best examples I can think of are in “Battle of the Bulge” and “From Russia With Love”.

The principle of a spigot launcher is very simple. Rather than fitting down a barrel the projectile has a tube that fits over the outside of the barrel. I have not encountered any examples of spigot launchers being used on rifles in the First World War. The principle was known at this time, since the Granatenwerfer 16 was an example of a spigot mortar.

When spigot grenades were introduced the rifles they were intended to be used with were not entirely suitable. Launching required an unobstructed length of barrel and a service rifle has structures such as bayonet lugs, foresights and woodwork in the way. The spigot launcher was therefore a length of tube that extended the barrel.

A number of spigot launchers for rifle grenades were in use in the Second World War.

The German example represents a very simple model of spigot launcher. It attaches using the bayonet lug and has a foresight for aiming grenades. The only projectile used was a 60mm hollow-charge anti-tank grenade.

The Japanese also made use of a spigot launcher. Two types of projectile were used. The fragmentation bomb was a Type.91 hand grenade with a tail unit screwed on. The smoke screening bomb was a dedicated rifle grenade weighing 1.3 lb and using HC composition.

The British produced a spigot launcher for the No.4 rifle. Like many designs it had a flip up ladder sight. This was marked in increments of 25 yd from 25 to 100. The No.85 51mm anti-tank grenade (1.26lb) externally resembles the M9A1. The No.87 was a WP rifle grenade (1.25 lb). Post war, this launcher could also use the No.94 Energa anti-tank grenade. One man per platoon was issued the Energa as a replacement for the PIAT.

The US had four models of 22mm spigot launcher in use during World War Two. The M1 was for the M1903, the M2 for the M1917, the M7 for the M1 Garand and the M8 for the M1/M2 carbine. The M76 was introduced with the M14 in the 50s. The M7 was not issued until late 1943 and the development of the M8 had been held back until the M7 was ready. Prior to this American forces only used grenade launchers on bolt-action rifles.

The exterior of American grenade launchers have grooves or rings. These are graduations used in setting the range of a grenade. By varying how far down the tube the grenade is positioned pressure and launch velocity can be varied. When the launcher was used for high-angle fire some means of keeping the grenade at the desired graduation was needed. For the M1 (M1903) and M2 (M1917) launchers a separate clip was attached at the desired level. Several of these clips were packed with certain rifle grenade types. The M7 and M8 had a spring fitted near the launcher’s muzzle. This provided sufficient friction to keep the grenade in place until fired. Apparently these springs were very prone to breaking until the A2 modifications after the war.

If a grenade was fired from the semi-automatic Garand the bolt would unlock before the grenade was fully under way. This caused a drop in pressure and reduced grenade performance. The M7 included a mechanism to shut off the Garand’s gas system, keeping the breech closed. When fitted with a grenade launcher it was necessary to hand cycle the bolt after each shot. By the Korean war the M7A2/A3 launchers were in service. These had a modification so they only shut off the gas system when a grenade was being fired. It was no longer necessary to remove the launcher to have the rifle function semi-automatically. The M1/M2 carbine had a different mechanism and functioned semi-automatically with or without grenades.

Many armies teach soldiers to hold rifles with the butt underarm when firing grenades at low trajectories. The US Army manuals do not mention this and taught that grenade launchers could be fired from the shoulder. Helpfully, it does suggest the butt be well seated against the shoulder, the thumb held on the outside of the grip and the head well back from the sight. A body position where the body can move with the recoil was required. If prone the shoulder should not be used. Instead some means such as a rut in the earth be used. When firing from a foxhole the back wall of the trench could be used. 

For high-angle fire the weapon was fired with the butt against the ground. A rubber recoil pad was available for the Garand. The carbine was held on its side so that both the heel and toe of the butt were in contact with the ground. The rifle or carbine was held at 30, 45 or 60 degrees and range adjusted by how far the grenade was slid down the spigot. Maximum range was increased by use of the “M7 Auxiliary Cartridge” (aka “Vitamin Pill”). This was a booster charge in what resembled (and may have been) a .45 Long Colt casing. The cartridge was inserted in the muzzle of the launcher before a grenade was fitted. The “Guidebook for Marines, 1951” cautions the auxiliary cartridge should not be used when shoulder firing due to “a tremendous wallop”. Use in the carbine was only for emergencies since the stock was not considered strong enough. Used of the vitamin pill was discontinued around 1954.

The different grenades had different ballistic behaviors, so for each there was a table showing which angle and “ring position” was required for a given range. 

A rotatable grenade sight (M15) with a spirit level could be fitted to the side of the stock. Interestingly, later field manuals for the M79 detail how M15 sights can be fitted to that weapon.

All grenades were fired by blank cartridges. This could be fiddly for the Garand. A cartridge was loaded directly into the breech (risking “Garand thumb” ) or the weapon unloaded and reloaded with a clip of blanks. Using a clip-loading mechanism the Garand magazine could not simply be topped up with blanks.

Blank cartridges for grenade projection are sometimes called “Ballistite” after the powder composition used in some examples. The term “ballistic” may also be encountered.

Ammunition for the American grenade launchers included:

M9/M9A1 (1.23 lb) 48mm hollow-charge anti-tank grenade. In a later war North Vietnamese forces used these fired from M44 Mosin-Nagan carbines.

M17 anti-personnel grenade. (1.47 lb) Mk2 “pineapple” grenade body with M9 rifle grenade tail. Impact fused.

M19 Smoke WP (1.5 lb). Screening, marking, anti-personnel and incendiary.

M20 Smoke HC. Screening smoke.

M22 Smoke Signalling. (1.26 lb) Emit coloured smoke for a minute after impact. Green, red, violet or yellow.

M23 Smoke streamer (1.16 lb). Before firing a section of tape on the nose must be removed to expose an air intake. Ten yards after launch produces a stream of smoke along its trajectory and for at least 12 seconds after firing. Green, red, violet or yellow. Maximum altitude Rifle: 155 yd in 11 sec, 203 yd in 12.4 sec with booster. Carbine: 97 yd in 8.5 sec, 133 yd in 10 sec with booster.

Parachute Flare. White, red, amber or green.

Five-star flare. White, red, amber or green.

M1-series Projection Adaptor. Tail unit for the Mk.2 hand grenade. A clip on one of the claws held the safety lever in position when the pin was removed. Firing causes the clip to setback and release the lever. Could also be used with the M34 WP grenade. Later model could be used with the M26 hand grenade. 0.38 lb plus grenade weight. WW2 60mm mortar warheads could also be thrown with this projector, for half the usual range. Later models of fuse will probably not arm if used this way.

M2-series Projection Adaptor. Tail unit for cylindrical, flat-bottomed grenades such as smoke, thermite, tear gas or the Mk3 offensive grenade.

During the Korean War it became apparent that something more potent than the M9A1 was needed. The US Army adopted the 75mm Energa grenade as the M28. A longer version of the M7, the M7A3, was introduced. The M28 was replaced by the M31, a 1.56 lb 66mm grenade of American origin. Performance of the two models is effectively the same, both giving around 200mm of penetration. 

High Trajectory Ranges:

M9A1 Rifle: 255 yd or 365 with booster. Carbine: 185 yd or 235 with booster. In theory it was possible for a high-angle shot to hit the thinner upper armour of a tank. In practice, the low velocity and wind effects made this difficult.

M17 Rifle: 200 yd, 290 with booster. Carbine: 135 yd.

Mk2 Frag in M1 adapter: Rifle: 180 yd or 225 with booster. Carbine: 130 yd.

Chemical grenade in M2 adapter: Rifle: 146 yd or 192 yd with booster. Carbine: 95 yd, 124 yd with booster.

M19/M20 Smoke grenades: Rifle: 215 yd or 310 with booster. Carbine: 150 yd or 215 with booster.

Flat Trajectory Ranges (up to 10 degrees elevation):

M9A1 Rifle: 104 yd or 175 yd with booster at 10 degrees. 215/315 at 25 degrees. Carbine: 70 yd at 10 degrees, 149 yd at 25 degrees. Time of flight about 25 yd in ½ second, 50 yd in 1¼ second. Lead for a target at 15 mph at 50 yd is 8 yd.

Mk.2 hand grenade in M1 adapter. Rifle: 50 yd in one second, 80 yd in 1.7 sec. Carbine: 39 yd in one second, 48 yd in 1.3 sec.

M17 Impact Frag. Rifle: 74 yds, Carbine: 51 yd.

While American soldiers were provided with grenade launchers and a wide range of ammunition types, it was noted in Infantry School Quarterly Vol.45-46, April 1956 p.82. “Rifle: grenades have long been a neglected and misused weapon, primarily because of misinterpretation and lack of information on their use. They are, however, the only antitank weapons of the rifle company other than the 3.5-inch rocket launchers. Not only are rifle grenades the antitank weapon of the rifle squad, they are also the squad’s “mortar” for indirect firing at area targets.”

A report on weapons use in the Korean War found no accounts of rifle grenades being used by US troops, although it did note there were incidences when they would have been useful. In all the units interviewed troops has thrown their grenade launchers away. The same report notes that the CCF (Communist Chinese Forces) did use grenade launchers. One wonders how many of these were items discarded by American troops!

While ingenious, the “ring and angle” range system does seem rather involved for a squad-level weapon that was intended to be used in close proximity to the enemy. In the trenches of Korea, grenade launchers may have been more effective if grouped into sections at platoon-level. Notable is that may other models of spigot launcher have rings or graduations, but do not appear to have a means of holding the grenade in a set position. This would not be the only instance of a piece of design being copied without understanding of function.

By the Vietnam-era the heavy M31 grenade was out of favour. It was not likely to perform adequately with the weaker 5.56mm ammunition and recoil would be even worse with the lighter M16. The M72 LAW and M79 seemed more promising. As is often its wont, disillusionment with one weapon caused the US Army to ignore the entire field. Potentially useful other types of rifle grenade were not made available to soldiers. For example, no adequate smoke screening round for the M79/M203 has ever been issued.

Some armies have remained enthusiastic users of rifle grenades. These include the Israelis, French, South Africans and Rhodesians. Belgium, Italy and China manufacture a range of models.

The Rhodesians often issued Energa grenades to the point man of a patrol, giving him RPG-level firepower during an encounter without the problems of back-blast and the added weight of a launcher. In a four-man Fire-force “stick” the two riflemen might each carry one or two rifle grenades.

The Rhodesians issued two cartridges for grenade projection. The full-power load (440 yd) was for high-angle fire with the butt against the ground. The reduced charge was for short-range (165 yd) “underarm” firing. It was considered a good joke to trick a comrade into firing the full-power load underarm or from the shoulder. It was prudent to keep your fingers out of the trigger guard and your thumb away from the pistol grip when firing grenades. The recoil could break them.

Using rifle grenades in semi-automatic rifles had introduced new complications. Propellant gases could escape from the opening breech or via the gas regulator. For many designs it was necessary to close the gas port to the barrel so the bolt could not cycle. The weapon needed to be manually cocked between each shot. On some designs the grenade sights are connected to the gas port. Flipping up the sight automatically closes the gas supply. Often a grenade cannot be placed fully over the muzzle if the grenade sights are not raised. Reloading the weapon with blank rounds was often slower with semi-automatics. Most self-loaders are not designed so that a magazine can be topped up with loose rounds while in position. The magazine needed to be removed, the chamber cleared and a new magazine of blanks inserted and a blank round chambered.

The original reason for the spigot launcher was that rifle barrels had not been designed with grenade launching in mind. This was to eventually change, and by the late 70s the latest designs of rifle had foresights not mounted at the muzzle and 22mm flash-hinders that also served as grenade spigots. Although assumed to be a “NATO standard” the common 22mm dimension was arrived at without official intervention. The various manufacturers emulated each other and were influenced by the rifle-grenades already in service.

The separate spigot launcher remained in use for some weapons. When creating the M14 from the Garand, the separate M76 launcher was developed rather than designing the flashhinder as an integral launcher. Some FAL rifles had integral launchers, while others (such as the British L1A1 SLR) required an attachment. The position of the SKS and AKM’s foresight required an add-on launcher for those nations that used rifle-grenades with these weapons. Below is a Polish example of an AK. External diameter of the launcher is 20mm. Many Yugoslavian SKS have grenade launchers. The Hungarian AMP-69 does not have a detachable spigot. Instead, the whole rifle has been reconfigured for grenade launching. A buffered stock and sliding fore-end help mitigate the effects of recoil. The gas tube is fitted with a cut-out.

As integral launchers became commonplace on military rifles spigot attachments became obsolete. Rifle grenades had not finished evolving, however. That is a story for another post.

Grenade Launchers: Raining Rods

In my last blog I provided some details about the seldom considered subject of cup grenade launchers. I promised to give a similar treatment to spigot launchers. I had intended to include rod grenades in that post, but instead have chosen to give this subject their own post. Since very few movies have been set in the trenches of the Great War, rod grenades are perhaps even less familiar to most people than other types of rifle grenade. The First World War as a genre is rather neglected, yet has potential for survival/ horror scenarios, if nothing else. 

Rodded grenades were widely used during the First World War. The Germans entered the war with two models already adopted. German units were amply provided with these, so the grenades seem to have been in full-scale production. These proved to be a great and deadly nuisance to those they were used against. Around 1917, when cup dischargers became more common, German use of rodded designs declined. The British had no rod grenades in service at the start of the war so developed a variety of models. Development continued until the end of the war and rodded designs remained in British service after cup dischargers became common.

As the name suggests, the rod grenade is a rifle grenade fitted with a long rod. The rod is inserted in the barrel of a rifle, and the grenade projected by firing a blank cartridge. While you will see the cartridges used to propel grenades called “blanks” it should be understood these are not the same as blank ammunition used for war games or TV shows. Using a normal blank with a rifle grenade (of any sort) will not get the grenade very far.

Many of the problems with firing grenades from cup dischargers were also true for rod grenades. Recoil damaged the furniture of the gun and affected the sights. Projectile flight was very susceptible to the influence of wind and other elements. Rodded grenades had some additional problems. The rod was effectively a barrel blockage so many rifles used for launching would succumb to bulged or burst barrels. Service rifles of the period were between 6.5mm and 8mm in calibre, necessitating that a rod be narrow. This, in turn, required the rod to be made of a relatively strong material if it was to avoid being easily bent or damaged. Damage to the rifling could occur, as could jammed rods.

Many of the practices later seen with cup dischargers had been developed for rodded grenades. Dedicated rifles, not used for normal shooting, were used as launchers and weapons were fired with their butt against the ground, never from the shoulder. In the trenches launching rifles were often mounted in firing racks. Sometimes these were arranged to create a battery of several weapons, and a means to fire all at once improvised. Trench mortars, machine gun nests and suspected sniper positions were often targeted. While mainly used like short-range mortars, grenade launchers were also used in more mobile roles. Some manuals and books of the time recommend that trench bombing parties included rifle grenades as well as hand grenades.

In British service a rod could be between 5½ and 17½ inches long, certain lengths being preferred for different models of grenade. Rod length had an influence on gas pressure within the barrel, and hence launch velocity and range. Longer rods increased recoil, while shorter rods caused the barrel to split sooner due to a longer path for reflected pressure wave effects. Incidentally, rod grenades required a different type of blank cartridge to cup dischargers. The lower volume in the barrel required a fast-burning, high pressure load. Some designs had a copper cup or plug at the base that was intended to serve as a gas seal. In practice this may fail to expand or fracture, causing range discrepancies. The length of the rod made the grenades awkward to carry in action. A bent rod could not be used, and a rod should be dry and clean before being inserted in a barrel, which could be a problem on the Western front. 

Range of a rod grenade was determined by barrel angle. German grenades also used attached discs to increase drag. In summer 1917 the British adopted an additional technique. It was found a rubber ring could be added to the rod to limit how far it inserted down the barrel and thus vary the velocity. The downside was it became more likely for an unwieldy 15 inch rod to be fitted.

Explosive rod grenades were either time or impact-fused. Ideally, the time fuse exploded as the grenade arrived at the target. If it was late it might burst in mid-air with little or no effect. An early round might bury itself in mud and thus throw few fragments. Impact designs had their own problems. Impact with soft mud or snow might fail to detonate the grenade and bury it. This is in fact a problem still encountered with modern grenade launcher rounds. Many Great War impact designs were overly sensitive and might detonate prematurely in mid-air. Worse, some would detonate on firing! The chance of the No.22 detonating in the launcher is reported as high as 2%! Many grenadiers mounted their launcher on a rack and fired it with a lanyard from behind cover. One presumes the No.22 was not suited to mobile operations such as trench-bombing raids.

British platoons were authorized eight rifle grenadiers. 

Eventually, a number of relatively useful designs saw widescale use with the British Army. The No.22 “Newton Pippin” was an impact-fused model. Its cone-like shape ensured that it arrived nose first. The fuse was noted for its “instantaneous” action. It would detonate on the surface of mud rather than within it and creating a crater. Fired against masses of barbed wire it would damage the wire, something much larger artillery shells often failed to do. Consequently, the fuse was adapted to use with mortar rounds for use against wire obstacles. At 1 to 1.63 lb, the No.22 was relatively light and could be launched at around 67 yd/s to 300 yd. It used a 15 inch rod with a copper gas seal. Depending on how the gas seal behaved maximum range might be as low as 220 yd or up to 350 yds. 

The No.20 (above) can be used for a more conventional British impact-fused rod grenade and to represent later evolutions such as the No.24 and 35. Weight 1.38 lb, 10 inch rod, 250 yds. For the earlier No.3 reduce range to 185 yd.

The No.34 “British Egg” hand grenade mentioned in the cup discharger blog could also be used as a rodded grenade. The only modification needed was to screw a rod to the grenade. As with cup launching, there was no need to strike the cap. If the safety pin had been removed the acceleration of launch was enough to shear the wire and start the seven second fuse.

The same igniter was used in the No.27 rifle grenade, a rodded WP grenade. Rod launch was used for smoke and signalling grenades as well as anti-personnel. Rodded grenades were used to pass written messages between positions, although some of these message carriers may have been grenades emptied of fuse and explosive. 

The No.23 version (1.53 lb) of the Mills bomb introduced a number of improvements over the original No.5, one of which was the facility to attach a rod to the base-plate. A 5½ inch rod is commonly illustrated, although one reference I have gives a maximum range of 160 yd with a 10 inch rod and 80 yds with the 5½ inch. No mention of the seven second fuse is made in references on the rodded Mills bomb. Interestingly, using the No.23 as a rifle grenade required a special muzzle fitting. This was held in place by a fixed bayonet and is a ring that holds the safety lever down while the grenade is loaded and the safety pin removed. When fired the grenade leaves the ring and the lever flies free.

German rod grenades of 1913 and 1914 were impact/ percussion fused designs of 2 lb weigh. Range was 350 yd for the 1913 and 380 yd for the 1914. Having entered service before the war, large numbers were available to German units. There were no safety pins, the designs being armed by the action of firing. They might also become live if dropped, especially on the tail rod. Live grenades might detonate when fired. Both models used 18 inch rods with a gas check. A tin disc could be fitted to the nose of the 1913 for firing at ranges of less than 200 yd. The 1914 had a saucer that was screwed between the grenade and the rod. Convex side forward this halved the range, concave side forward it quartered it.

The Germans were amply provided with rod grenades and made frequent use of them. At the start of the war they also enjoyed an advantage in trench mortars. The British soldiers were subjected to rains of bombs and grenades with no weapon that could counter them nor equivalent of their own.

Once they had their own models, the British also used rod grenades in considerable numbers. In July 1916 two reinforced companies from the Royal Welch Fusiliers expended thousands within a few hours. In August 1915 Field Marshal French (British Army) has asked to be supplied with 112,000 rifle grenades per week (actual supply raised to 19,000).

Allegedly, American soldiers with trap or skeet-shooting experience were provided with M97 Trench guns and placed in positions where they could fire on incoming rifle grenades.

There are very few examples of rodded grenades after the war. Some “anarchist”manuals describe shotguns (which may themselves be home-made) converted to grenade launch by using projectiles with dowel rods. The larger bore and other characteristics of shotguns permit construction methods different to the First World War grenades. This may be easier to improvise or manufacture than a cup discharger.

A company called Precision Ordinance produces the M444, a very long, narrow stun grenade that can be fitted down and launched to about 100 yd from a 12g shotgun barrel. It can also be pushed or thrown through small holes, such as those made by a shotgun damage.

Some mortars and artillery have used muzzle-loaded projectiles with rods that passed down the barrel. The German 15cm heavy infantry gun (s.IG33) used a 200 lb Steilgranate 42 “stick bomb” with stabilizing fins that remained outside the barrel. This projected a warhead containing 60 lb of explosive to 1,100 yd and was used against strongpoints and wire obstacles. Similar in design was the Steilgranate 41 fired by the 37mm PAK 36 anti-tank gun. This was a 19 lb shaped-charge projectile with 180mm penetration. Maximum range was 880 yd, although 330 yd was a more likely engagement range. The Japanese Type 98 50mm mortar (not to be confused with the Type 89 50mm “knee mortar”) is another example. 

GURPS High-Tech 3e describes TL4 rodded grenades. I do not know if there is a historical precedent for these. The greater bore-size of a musket allows the rod to be tube of powder. p.46: “Another kind of explosive is a rodded grenade. It can be fired from any smooth-bore shoulder gun. The rod is hollow, and filled with an incendiary compound to serve as a fuse. The rod is fitted down the barrel, and the gun fired - with a blank charge, of course! If all goes well, the powder charge both propels and ignites the grenade...Weapon stats for rodded or cup-launched grenades are different than for the same weapon with ball. Damage, as a projectile, is 1d. Explosive damage is normal for a TL4/5 grenade. Half-damage range is meaningless for a launched grenade; maximum range is 100. Accuracy is 2; Snap Shot is 10...A [TL4] rodded grenade can be picked up and thrown, if it does not explode - but the fuse cannot be extinguished. On a misfire of the launching weapon, the fuse of a rodded grenade does not ignite.”

Grenade Launchers: The Cup Dischargers.

The grenade launcher section of High-Tech 4e p.142 primarily describes the “grenade gun”-type of launcher, such as the M203 or AGS-17. For other types of grenade launcher we need to look under “rifle grenades” on page 193. This makes the rather deceptive statement that “While this [a cup or spigot] is present, the gun cannot fire normally.”. The rifle could still fire bullets with a launcher in place. Most cup dischargers will block the use of the normal sights. A set of raised sights could have been fitted, but this was seldom done, the operator being expected to either remove the launcher or reserving the rifle for grenade firing only. A spigot launcher might only affect normal shooting if the grenade sights were raised. Certain rifles were operated normally with the launcher permanently affixed. I will cover spigot launchers and how they may affect shooting in another blog. Since High-Tech only mentions one type of cup discharger launcher I thought it might be interesting to look at these in greater detail.

I will use “grenade launcher” in the older English manner. In some languages the terms “shell” and “grenade” are effectively interchangeable. This use has creeped into English in recent years, as seen in the backronym such as “rocket-propelled grenade”. The Germans call some mortars “Granatenwerfer”. In Russian the term “grenade launcher” is taken to include many designs of rocket-launcher and recoilless weapon. The term cup discharger is also used for vehicle-mounted smoke round throwers.

These weapons will be unfamiliar to many readers. Seldom are they seen in movies. Information on rifle grenades, and particularly cup discharger launchers is not commonly encountered. What information there is is often incomplete or unclear. I have had to make educated guesses in places. Many books on infantry weapons totally ignore the category. Yet more the 1.45 million of the Schiessbecher model alone were produced. Many designs served for several decades and similar devices are still used for riot control. Novelty devices that can launch golf balls or soda cans from rifles can be purchased. I believe a device similar to the former was used for assassinations in an episode of the (Steed and Peel) The Avengers.

All ranges are approximate. Effective range depends on many factors, including weapon accuracy, target size, effect area and target speed. A weapon with a small effect area needs to be got closer to the target than one with a larger area. All rifle grenades (not just those from dischargers) are low-velocity projectiles and are very subject to the vagaries of the wind. A head wind may significantly decrease range, a tail wind increase it. Cross winds will cause drift. The long fuse durations used with rifle grenades will give an idea of typical times of flight to a target. The long time of flight was also detrimental when engaging moving targets, such as when using anti-tank grenades.

The cup discharger dates back to at least 1743. Cups that could be mounted on the muzzle of a flintlock musket, utilizing the the lug for the socket bayonet, are known. These gave the musket a similar capability to earlier “hand mortars” that were designed to project grenades.

Che Guevara described how a single-barrelled 16 gauge shotgun could be modified into a mortar-like weapon using a pair of rods or sticks for long bipod legs, and an assembly like a cup discharger. Similar weapons have been used in the Middle East. Such weapons can launch grenades, Molotov cocktails or pipe bombs to at least 100 yd and are easily constructed.

In modern times, cup dischargers are most commonly seen launching riot control munitions. One of the advantages of cup dischargers in this role is they can launch unmodified hand grenades. Typically the launchers are of around 66mm/ 2.5" calibre. The body diameter of the grenade used may be slightly less since the discharger must often accommodate the safety lever to. Cup-dischargers for riot munitions are produced for modern, 5.56mm and 7.62mm automatic rifles. Many police forces mount them on obsolete (often bolt-action) rifles, often with shortened barrels. Dischargers for 12 gauge shotguns, flare guns, .38 revolvers and 37-38mm riot guns also exist. The revolver mounted Smith & Wesson models launch a 38mm munition. 

Notable is a model by the Israeli company of ISPRA which has two different diameter cylindrical sections. One part can take spherical grenades such as the 83mm rubber pellet grenade. The smaller part can take cylindrical grenades of around 64mm. 

Discharger, Grenade, Anti-Riot L1A1 is effectively a cup discharger without a rifle. It resembles a 66mm vehicle smoke grenade launcher fitted to a tubular stock and pistol grip. Weight: 5.94 lb, 110yd range. Grenades 1.21 lb. The grenade propellant is ignited electrically by a pair of 1.5V U2/D battery. When firing a button behind the cup must be depressed by the off-hand, so the launcher can only be fired two-handed. The launcher is mainly used with CS irritant grenades but can also launch smoke-screening grenades. It was primarily used for riot control in areas such as Northern Ireland rather than as a battlefield system.

The heyday of cup discharger use was the First and Second World wars. During the latter half of the First World War it began to be realized that the rifle was no longer the last word in infantry weapons. Even today, some armies still try to resist this idea! The Great War sees a shift towards the light machine gun, hand grenade and grenade launcher becoming the primary firepower of a squad.

The VB cup launcher, aka Viven-Bessières or “Tromblon” was a French device used on the 8mm Lebel rifle from 1916 onwards. It weighed 3.3 lb and was 50mm calibre. The launcher itself is very simple, the novel element being the design of the projectile. The explosive projectile had a channel down its centre and was fired by a conventional ball round, rather than a blank, which is more usual for cup-dischargers. The passage of the bullet tripped a lever which initiated the fuse so the grenade exploded 8 seconds later. Range was up to 208 yards. The projectile weighed 1 lb and does not seem to be capable of use as a hand-thrown grenade. Range was determined by varying the launch angle and no special sighting systems seem to have been used with the VB. Smoke and illumination projectiles were also issued, but were launched by a blank. Also in use was a container that could carry a written message. This released yellow smoke so that it could be more easily located, but in practice the smoke volume was very small and difficult to spot. One suspects that the projectiles often buried themselves in the abundant mud of the western front. The French considered the VB a company-level weapon so several might be fired together at the same target, particularly in static, trench operations When fired from trenches the rifles were often placed in special racks, some designs of which could be set to variable elevations. The VB continued in service after war, but like similar weapons, seems to have migrated into as squad-level weapon. A French Foreign Legion cavalry platoon had two machine gun sections and two scout sections, each of the latter having a VB. The French Army was still using it at the start of the Second World War. Some VBs saw action in remoter areas of the French Empire, such as the Philippines. The VB continued to be used as a riot grenade launching for several decades after this, at least up the the 1990s.

The VB design was adopted by the American Expeditionary Force in 1917 for use with .30-06 M1917 Enfield and M1903 Springfield rifles. These launchers did not remain in US service long after the war.

The use of a ball round required that the barrel and the channel in the grenade remain properly aligned. This required that the launcher and grenade be manufactured to an adequate level of precision and that the launcher not allowed to work loose when fitted. Firing a ball round at up to 45° in the air was a safety concern at practice ranges, since the bullet could land miles away, still at lethal velocity. A training round using a very light wooden bullet was developed.

While the French (and later Americans) selected the VB, the British chose to develop their own design, settling on the Burns Grenade Discharger, which was trialed in France in 1917. This later became more commonly know as the “EY”. This had a calibre of 2.5" (66mm). Originally designed for the .303 SMLE, adaptors and variants were created that allowed use with the .303 P14 (No.3 rifle) and .300 (.30-06) P17 (M1917 Enfield). Using blank cartridges, the basic launcher could be used with either calibre. The Burns/ EY was intended to be always fired at 45° and range varied by degree that the gas port was opened or closed. (Automatic rifles with a “vent to atmosphere” gas system need to have their gas port closed when using rifle grenades, otherwise the inertia of the grenade forces most of the gas out the port and the grenade is moved only a few yards, if at all. Seeing the term “gas port” in connection with a bolt-action weapon may seem confusing!). The gas port for the EY is on the launcher itself and is a vent resembling a sliding shutter. A tightening knob prevents the shutter moving from the desired setting. One model of EY used a rotating ring with a number of holes instead. With the port full open (all the holes over the port) range is around 80 yards. Fully closed, range is around 200 yards. Note that the EY was fired with the rifle “upside-down”, with the trigger guard upwards. This placed the heel of the stock in contact with the ground for better management of the recoil forces. When used in the First World War trenches a variety of stands were used with these grenade launchers, some of which could be varied for elevation, even though range was supposed to be controlled by the gas port setting. No sight was provided for the Burns/ EY until the adoption of the no.68 grenade.

The usual fragmentation grenade for the EY was the no.36/ 36M Mills Bomb. These were modified by adding a “gas-check” disc that screwed into the base plug. A 7 second fuse was commonly fitted instead of the 4 second. The grenade is inserted into the launcher and the pin removed. The wall of the barrel keeps the safety lever in position until the grenade is fired. Grenades modified for launcher use could still be used as hand grenades, the base disc having no effect on throwing. One of the reasons for the gas-check disc was that the Mills Bomb is around 60mm and the launcher was designed to also launch larger diameter cylindrical grenades such as the no.37 (WP) and no.80 (WP). Illumination rounds were also available. 

A Mills bomb weighed around 1.7 lb and launched at around 47 yd/s, so the recoil of firing the launcher was around three times that of firing a bullet. This was why the rifle was held so that the heel was in contact with the ground. If the ground was hard it was recommended that a sandbag be used. Users were cautioned to keep their hands away from any metal parts when firing. The harsh recoil would affect sight alignment so the EY was used on rifles that were only intended for grenade launching. Reinforcing bolts and wire wrap were used on certain parts to counter the woodwork cracking. One of the explanations for the name “EY” is that many of the rifles used were stamped EY, this being an armourer’s abbreviation for “Emergency Use only”, many guns tasked with grenade launching being non-longer suitable for general use.

In 1940, the no.68 shaped-charge anti-tank grenade was adopted for use with the EY. This role required the launcher to be fired at shallower trajectories (10°) so a dedicated sight was fitted. The end of the grenade projected past the muzzle of the launcher and the horns of the sight were aligned with the curve of the end of the grenade. A variant sight had a stepped cut-out, permitting it to be used with either the .303 SMLE and P14 or the .30-06 P17. The British Army had adopted the No.4 Lee Enfield but the EY seems to have been fitted on the by then obsolescent SMLEs. The Home Guard was using SMLEs, P14, P17s and Ross rifles. The no.68 grenade weighed 2 lb and low angle shooting required inventive ways to handle the increased recoil. It was recommended that the butt be placed on soft turf or a partially filled sandbag. It should never be used from the shoulder. If fired from the hip it was cautioned that no part of the rifle should be in contact with the body. Penetration was 52mm.

When the 2.5" launcher was being trialed in autumn 1917 experiments were conducted with a version designed for the No.34 “British Egg”grenade. The No.34 was a design that had been created by the British Army in France and was felt by some to have some advantages over the Mills, which had been invented in Britain. The two models had possibly complimentary roles. The No.34 weighed 0.65 lb and was 41mm in diameter. Weight for weight it produced 30% more fragments that the Mills. It could be hand-thrown to a greater distance, so the user was in less danger from fragments from his own grenade if the weapon was used in the open. Fired from its cup discharger the No.34 had a range of 500 yd, compared to 200 for the No.36. The Mk IV version of the No.34 added a ring cast around its widest point that served as a gas check. The igniter of the No.34 used a striker pellet held by a safety pin and a shear wire. This igniter (“Adams striker mechanism”) was used by some other grenades intended for discharger launch, including the No.37. Once the safety pin was removed, the acceleration of launch caused the striker pellet to break the wire and start the 7 second fuse burning. There was no danger that a grenade might be accidentally inserted with the safety lever outside the cup since there was no safety level, the fuse being triggered by the violence of launch. For hand-throwing, the striker pellet was hit against a hard object such as a helmet or boot-sole. A fuse working the same way was used in many Japanese Second World War grenades. These too, activated automatically when launched from the Type 100 cup discharger or knee-mortar. Potentially, the No.34 Mk IV may have been the better discharger round. The lighter weight may have meant reduced recoil forces as well as longer range. The long narrow shape of the grenade may have given a shorter time of flight, contributing to accuracy by reducing the effects of wind on the grenade. The idea that a soldier might carry two different calibres of cup-discharger was rejected. Perhaps the larger version was selected since it could handle other models of grenades such as the No.37. With hindsight, a dual calibre design along the lines of the later ISPRA could have been tried. Or a sabot, as used on the later Yugoslavian RB-100 grenade. This, and other earlier Yugoslavian grenades, particularly the Mod.1917 grenade, bears a striking similarity to the No.34. Overcaliber rounds, such as used with the Schiessbecher might also have been tried.

Around 1925 the British Army adopted a 2" version of the cup discharger. Intention may have been to address issues such as recoil and eliminate complications such as gas-checks that the variety of grenade calibres necessitated. A range of 2-inch grenades intended for use with this launcher included the No.54 fragmentation (17oz) , No.55 WP-smoke and a variety of signals and illumination. The No.54 and No.55 use a “weighted tape”-type “Allways” fuse, of similar principle but apparently different model to the No.247 used on the later No.69, No.70, No.73, No.77, No.79 and N0.82 Gammon grenades. The “Textbook of Small Arms 1928” gives the range of the No.54 as more than 300 yd. It also tells us this model can be attached and used without detaching the bayonet. A portless model that used angling for range was considered, but some form of vent was found necessary for engaging short range targets.

In 1933 the 2.5" launcher was readopted. The Mills bomb had remained in service. The Textbook of Small Arms 1928 describes the No.37 with no indication that it was at that time considered obsolete.

As I have already noted, information on cup dischargers is relatively hard to come by. I have found no information on if the EY could be easily mounted on the No.4 or No.5 Lee Enfields, nor if so, whether this required an adaptor to accomodate the differences in muzzle configuration. I have yet to encounter any information on scale of issue in British service. The grenade launcher was presumably a squad or platoon-level weapon, but I have no information on how common or what numbers they were used in.

The EY was in use at least as late as the Malaya Emergency. The photo below shows a shortened Lee Enfield with an EY. This one is Irish or British, but other armies and police forces created similar. This one is claimed to have been used in the 1960s, presumably for riot munitions. The red markings on the magazine may be a caution to use blank ammunition, a notification the weapon uses .303 rather than 7.62mm, or both. Interestingly, the rifle has an aperture rear-sight so is either a No.4 or No.5 rather than a SMLE. The recoil pad of a No.5, or a No.5 stock with a recoil pad, has been fitted. 

(Above) A non-EY smoke grenade launcher of a type used on universal carriers. The rifle part is a cut-down SMLE.

During the First World War the Germans copied the VB. Battalions had a squad of rifle grenadiers. Their Gew.Spr.gr 1917 grenade had a 5-8 second fuse, weighed 1.76 lb and had a range of 165 to 220 yd. As the war progressed the grenade launcher became a weapon of smaller units. The Schiessbecher was adopted in 1942, one launcher being held per rifle squad. The Schiessbecher was used on the Mauser Kar 98k and also a number of other rifles including the StG44, G43 and FG42. PzB 39 anti-tank rifles were shortened, modified and fitted with a Schiessbecher to create Granatbüchse Modell 39 (GrB 39) Weight: 23.15 lb, single-shot. The anti-tank rifle used a 7.92/13mm round so the propellant cartridge for grenades was based on a 13mm case. This gave a longer range than the launcher mounted on other rifles. Light anti-tank grenade: 0.55 lb 250 yd range, heavy anti-tank grenade: 0.8 lb 120 yd).

The Schiessbecher is described briefly in the rifle grenade section of High Tech 4e. The Schiessbecher is notable for being rifled and only 30 mm calibre.

The diameter of most cup dischargers prevents the use of the standard rifle sights. It is possible the No.34 launcher and 2-inch launcher may have been exceptions. The Schiessbecher does appear to allow the normal use of the rifle while fitted. The sights of the StG 44 are raised well above. There are numerous photographs of Kar 98k mounting Schiessbecher being aimed at low trajectories, suggesting bullets rather than grenades are being aimed. 

For firing grenades, a rotating sight incorporating a spirit level may be mounted on the left side of the weapon. Often the discharger is used without the sight. There is no gas vent, range being selected by barrel angle.

All grenades were fired by a blank round or a case mounting a wooden bullet. Each different grenade type used a particular propellant round. These were distinctively marked and packed with the appropriate grenade. The relatively light weight of the grenades produced less recoil than the EY. This was an advantage since the anti-tank and anti-personnel grenades might be used in a direct fire rather than high trajectory role.

The use of a shaped-charge favoured larger-calibre projectiles. Some anti-tank rounds resembled toadstools, having a 30mm stem that fitted in the launcher and a larger diameter head that remained outside. All Schiessbecher are spin-stabilized, which reduces the effectiveness of a hollow-charge.

High explosive grenade: 30mm, impact or allways-fused. Some models self-destructed 11 seconds after firing if an impact failed to detonate them before. Some variants could be used as hand grenades. These employed an operation similar to the stick grenade: the base of the grenade was unscrewed, the cord pulled and a 4½ second fuse ignited. 0.56 lb, maximum range 265 yd. A long-range version propelled by a wooden bulleted cartridge claimed a range of upto to 711 yds. This model lacked the self-destruct feature.

30mm (light/Klein) anti-tank grenade: 0.55 lb, maximum accurate range 50-123 yd. 25-30mm penetration. Velocity approx 55 yd/s

40mm (large/Grosse) anti-tank grenade: 0.84 lb, maximum accurate range 100 yd. 40mm penetration.

46mm anti-tank grenade: 0.97 lb, 90mm penetration. range 110 yds, maximum 200 yds.

61mm anti-tank grenade: 1.19 lb 126mm penetration. extreme range 220 yd. The 46mm and 61mm anti-tank grenades had been developed independently by the SS.

39mm Smoke grenade. Titantetrachloride (FM), 1.39 lb. Had a grooved skirt which fitted over the outside of the Schiessbecher.

30mm Parachute Illumination 0.62 lb Ejects a parachute flare 8½ seconds after firing. Burns for 25 seconds, illuminating targets up to 765 yds away.

30mm Propaganda leaflet grenade. 0.5 lb (loaded with leaflets), ejects 0.125 lb of leaflets 9 seconds after firing. Maximum range is approximately 500 yards.

Japanese used the Schiessbecher as the Type 2 and their own design, the Type 100 cup discharger.

The Type 2 fitted the Type 38 and Type 99 rifles. Ammunition was a 30mm and a 40mm hollow-charge anti-tank rounds. The 30mm weighed 0.5 lb and gave 30mm penetration of armour. The 40mm weighed 0.81 lb and gave 50mm. They did not prove effective against American tanks in Burma.

There was a variant of the Type 100 for the 6.5mm Type 38 rifle and another for the 7.7mm Type 99. The bayonet must be fixed to secure the launcher in position. When in position the launcher prevents the use of the normal sights. Ammunition is Type 91 and Type 99 grenades. The safety pin is removed and the grenade placed in the cup striker pellet downwards. Grenades are fired with the rifle butt against the ground. The Type 100 used ball ammunition and diverted the propellant gases into a cup mounted on top of the barrel extension. The effective range is approximately 100 yards.

The Japanese “Knee-mortar” could also project modified hand grenades and is sometimes designated “50mm Grenade Discharger”.

The Soviets used the Dyakonov grenade launcher. Designed in 1916, it was not adopted until 1928 and dropped from service in 1942, so was likely to have seen action in Soviet-Japanese Border conflicts, the Winter War and early Second World War. The Dyakonov appears to be a rifled VB-type weapon of 40.5-41mm calibre (probably 40.8mm, “16 lines” in older Russian measurements). A booster charge seems to have been incorporated in some projectiles. The Dyakonov was mounted on a standard M1891 Mosin-Nagant rifle, fitted in place of the socket bayonet. After the war some M44 and SKS carbines (which both had folding bayonets) were adapted to this launcher.

Recoil was harsh, so the weapon was fired from the prone position with the butt dug into the ground. Firing from a hard surface or frozen ground could be problematic. In 1939 a Dyankonov was supposed to be held by each rifle squad. The Dyankonov was operated by a crew of two, the loader carrying 16 grenades.

The launcher weighed 2.9 lb, the quadrant sight 1.5 lb and the bipod 4.9 lb. Rifle and all fittings weighed 18.1 lb.

The anti-personnel round (0.83 lb) had a timed fuse that was set manually with a dial on the base before loading. Range was 330 yd, with up to 930 yd claimed if the booster charge was left in place on the base of the grenade. Casualty radius was about 33 yd, but fragments are claimed to travel up to 165 yd, potentially reaching the launcher team.

Day signal. Adopted 1936, weight 0.3 lb. Launched by a blank round to a range of 200-250 yd. After a 2½ second this burnt to release red, orange, yellow, blue or green smoke. The smoke burns for 20-40 seconds and may be visible for 60 to 90 seconds.

Night signal grenade. Adopted 1936, weight 0.375 lb. Star of red, yellow, blue or green. Launched by a blank round to a range of 165-250 yds. Signal burns for 10-11 seconds. May be visible 10-12km away or as much as 25km under good conditions.

Illumination grenade. Adopted 1936, weight 0.375 lb. Launched by a blank round to a range of 165-250 yds. Burns for 6-7 seconds, illuminating a radius of 110 yd.

The Dyakonov explosive round proved to be ineffective and unreliable. Despite the two-man crew, rate of fire was only 3-4 rounds per minute. Designed for the positional warfare of the Great War, the system was ill-suited to the often more mobile warfare of the era it was used in. The signal and illumination rounds had a useful performance but had durability and reliability issues.

The VKG-40 hollow-charge anti-tank grenade was fired from a modified Dyakonov launcher, adopted in 1944. Once modified the launcher could not fire other types of Dyakonov grenades. The VKG-40 was a rodded grenade. The anti-tank round was projected by a special blank round to 165 yd. Armour penetration was 50mm and weight was 0.48 lb. The round was only suited to attacking very poorly armoured targets, and like other grenade launchers the long time of flight, high trajectory and wind effects made it difficult to engage moving vehicles.

Tromboncino M28 (“Little Trombone”) was an Italian grenade launcher of the interwar period, which was in service until 1934. While it does not seem to have seen any significant use, the design is interesting since it shows some features used in much later grenade launchers. It was mounted on the right side of the 17-inch barrelled 6.5mm Carcano M91TS carbine (6.4 lb), portending weapons like the M203. To use the launcher, the bolt had to be removed from the carbine and fitted to the launcher. The single trigger fired either the carbine or the launcher, depending on which the bolt was inserted in. The grenade launcher fired a 38.5mm impact-fused, cast-iron, finned grenade of only 0.36 lb to a range of 220 yd. The grenade was projected by a ball round, and is an early example of a bullet trap mechanism. The launch mechanism also had features of a hi-lo pressure system later used in the M79 and M203.