RIFLE GRENADES
GRENADE LAUNCHERS
Tromboncino [trombonˈtʃiːno]: diminutive of Trombone, but not necessarily the 15th century musical instrument: Trombone in Italian indicates a large Tromba (trumpet).
Tromba derives by the old latin for Tuba, which indicates both the lead tubation and the ancient musical instrument, later modified by German languages into the term Trumba.
The word Trombone was used since the 16th century to indicate handheld bluderbusses, indicating, again, a large tromba-like object, because of their conical shaped muzzle. Then Tromboncino was used to indicate a small blunderbuss.
When flash hiders were introduced as a gun accessory in the late 1800s, they were conical shaped; and, again, looked like a trumpet end, so they got named Tromboncini in Italian terminologies.
When barrel mounted grenade launching tubes were introduced (for the Bertone and Vivien-Bessiere Grenades) they got quickly nicknamed Tromboncino too, especially since the french would do the same, naming the launching tubes for the V-B “Tromblon”.
The complete Italian name for these devices would be Tromboncino Lanciagranate, to differentiate it from the Tromboncino Spegnifiamma/Rompifiamma (Flash hider).
FIRST WORLD WAR
- AASEN
- BENAGLIA
- BERTONE
- EXCELSIOR-THEVENOT P3
- VIVIEN-BESSIERE
- PROTOTYPES
INTERWAR PERIOD
- TROMBONCINO MOD.28
- “TERNI” PROTOTYPES
- BREDA PROTOTYPES
SECOND WORLD WAR
- TROMBONCINO MOD.43
- PROTOTYPES
POSTWAR PERIOD
- TROMBONCINO MOD.61
- TROMBONCINO MOD.63
FIRST WORLD WAR
AASEN
In 1906 the Norwegian inventor Nils Waltersen Aasen patented a rather modern and effective hand grenade system. He further developed it and, since the Norwegian government was not interested in the project, he founded his own company in Denmark, under the name Det Aasenske Granatkompani.
This new weapon system was a commercial success, being rapidly adopted by several European nations, including France and Italy in the years immediately preceding the First World War.
Italy in particular adopted both the hand grenade and rifle bomb variants already in 1912, for use during the Italian-Turkish war.
During the First World War, these grenades were reused during the early stages of the conflict, only to be replaced by more modern models introduced in later stages of the war.
What’s peculiar about the Italian adoption of this grenade is that it was introduced into service to be fired with a mod.1870 carbine instead of the mod.91 rifle.
In 1915 some of these were modified with a thinner guide rod and a disc at the base of the grenade, useful to perfectly blocking the gas vent at the moment of the shot.
The grenade, having inserted the guide rod into the barrel of the rifle, was projected through the use of special blank cartridges, loaded with 0.475g of solenite for medium distances (green cap, a notch marked on the bottom) or with 1g of solenite for long distance (Yellow cap, two notches marked on the caseback).
The maximum range was about 300 meters, and the trajectory depended greatly on environmental factors (especially any wind).
The grenade was triggered in the air thanks to the propeller placed on the front unscrewing the safety system, and exploded when it hit the ground, projecting 72 cast iron balls within 7 meters.
BENAGLIA
Upon entry into the war, the Italian General Staff quickly realized that trench warfare required greater innovations, especially from the point of view of infantry armament.
Experiments immediately began with a new type of rifle grenade, called Benaglia after its creator.
This consisted of a cast iron casing filled with explosives, with a firing pin activated by impact on the ground. The guide rod at the base of the grenade was inserted into the barrel of the rifle or carbine: a special cartridge was inserted (essentially an ordinary mod.91-95 cartridge without ball, plugged at its neck with a cardboard disc) and the shot was fired, tilting the rifle in the direction and angle indicated by the commanding officer.
Between the summer of 1915, and 1916, when it was formally adopted, several experimental models were developed in succession, each with different primers, cast iron molds, firing pins, loading caps, and stabilizing fins. In particular, the first models had a wooden base to give it an aerodynamic shape, to which several fins of sheet metal were added to stabilize the fall.
There were several variants that remained at the prototype level or were distributed in small batches, the most famous of which were a “Gussi” variant with a sheet metal “skirt” that guaranteed aerodynamics during the fall phase.
At the end of the experiments, the final shape with three fins fixed directly to the steering rod via a nut was adopted, despite a large batch of wooden base grenades was produced nonetheless.
F.A.R.E., Fabbrica Apparecchi Riscaldamento Elettrico Milano, produced about 650,000 grenades, in coordination with Rome Artillery Directorate.
It remained in production and use until the end of the war.
BERTONE
This rifle grenade was adopted in early 1917, inspired by the Vivien-Bessiere. As for the VB, it was fired from a launch tube mounted on the barrel of the rifle or musket, and was operated using ordinary 91-95 cartridges.
Upon firing, the ball passed through the bomb, triggering an ignition capsule. The detonator fuse then had a delay of 9 seconds. After this, the bomb was projected forward by the gases of the shot which followed the ball.
The maximum range was 250 meters with the rifle and 300 meters with the musket, and its splinters could reach a distance of 50 meters when fired. Hastily put into mass production, several issues soon arose, both in terms of manufacturing defects and soldiers reporting serious incidents during its use.
Because of this limited reliability and smaller explosive charge compared to its French counterpart, production was halted in 1917. However, it remained in use until the end of the conflict, and it is still represented in 1919- 1920 army manuals.
Cpt. Emanuele Balbo Bertone di Sambuy
EXCELSIOR-THEVENOT P2/P3
When Italy entered the Great War alongside the Entente powers, it began to receive large quantities of food, weapons, and ammunition.
In particular, Italy obtained various equipment from its French ally, in the form of artillery, machine guns, Saint-Etienne models, and rifles (Lebel and Berthier), especially after Caporetto, but even before some models seeped through.
Among other supplies, France also provided several Excelsior-Thevenot P2 hand grenades, and P3 rifle bombs, along with the information needed to produce them.
The Excelsior-Thevenot bomb was very similar to the grenades developed by Aasen, both in shape and operation. In fact, even the E-T had a propeller on their top which, along the fall trajectory, rotated, unscrewing the safety and allowing the firing pin to be activated upon contact with the ground.
The main difference between the E-T and the Aasen was the presence of a safety pin which held the entire mechanism in place during transport.
The P3 rifle version differed from the hand grenade version in that it had at its base, instead of a wooden handle, a guide rod with a sheet metal tube around it, so as to fit correctly into the rifle barrel and to mantain an aerodynamic shape during flight. This way the bomb could fall on its head, releasing the firing pin upon impact.
Examining various diagrams and instructions reveals another difference between the P2 hand grenade and the P3 rifle grenade.
The P2 had a body (covered in sheet metal) made up of cast iron balls held together by a resinous material, while the P3 had a body (still covered in sheet metal) of cast iron, with the grooves necessary for fragmentation.
Weighing around 400 grams of which 80 grams of “Echo” explosive, it had a maximum range of around 200 meters and had a radius of action of around 20 metres. They were fired with a cartridge with a wooden cap instead of a standard bullet.
There was also a variant of the Excelsior Thevenot that could be fired directly from an independent sheet metal tube with a built-in charge. This disposable device was the version called AF.
VIVIEN-BESSIERE
Created by the French in 1916, it arrived en masse in Italy only after the events of Caporetto, at the beginning of 1918, along with countless other war aid provided by its French ally.
The Vivien-Bessiere functioned similarly to the upstated Bertone shoot-through rifle grenade. It was positioned in a special launching tube placed at the muzzle of the barrel, being fired with an ordinary cartridge.
Upon firing, the ball passed through the bomb, triggering an ignition capsule (H in the drawing) which initiated the detonator fuse, with an 8-second delay. After this, the bomb was projected forward by the gases of the shot which followed the ball.
Weighing approximately 450 grams of which 60 grams of “Cheddite” explosive, it had a maximum range of approximately 180 meters and had a radius of action of around 50 metres.
A conversion adaptable to the mod.91 rifles was tested, but this was not carried forward as the caliber of the ball and the gases released by the mod.91-95 ammunition were often unable to launch the bomb at the desired distances nor to trigger it effectively.
Therefore these grenades were mostly used in the Lebel and Berthier rifles offered as war aid.
PROTOTYPES
BOMBA P.E. PER FANTERIA (PIERSANTELLI)
Prototype we know very little about. Basically, it was an accessory applicable to Mod. 91 rifles, firing a 350-gram, 15 cm long grenade, with 1,000 cast iron splinters per warhead (sic).
The range was approximately 400 meters (at least this is what is reported on the finds in our possession), a very optimistic distance for an artifice of this size.
The grenade was launched through an exploding charge contained in the tube placed behind the grenade, activated by a spring firing pin (operated by hand).
Never went into production
Collezione Taglier, tramite R.Stevanin
INTERWAR PERIOD
TROMBONCINO MOD.28
In the second half of the 1920s, after the experiences gained during the Great War and the “pacification” campaigns in Northern Africa, the Ministry of War issued a request to equip infantry squads with greater direct support during close combat, especially during operations not directly covered by artillery fire.
The requests (based on the designs, patents, and prototypes that have come down to us) for early 1927 trials were as follows:
- The new Tromboncino weapon system had to be mountable on the Mod. 91 TS carbines (or the Mod. 91/24 variant).
- The Tromboncino must not have prevented in any way and at any time the regular use of the carbine, therefore it had to be mounted in a special separate position.
- The Tromboncino had to be capable of projecting an explosive grenade of approximately 40mm in diameter at a distance of at least 200 meters.
- The Tromboncino had to project the grenade using ordinary ball ammunition mod.91/95.
- The Tromboncino had to be operated with the same trigger as the Carbine.
- The tromboncino had to use a 200g grenade, capable of exploding despite the angle of impact and ready to be throwed by hand in case of emergency. To execute this in complete safety, the base request was to use a smoothbore launching tube.
MBT and Breda most likely participated in the tender, along with others. Although we have no certain information/documentation on the matter, it seems that the winning Tromboncino model was the one presented by Terni, formally adopted as the Tromboncino mod.28 (and mostly produced by MBT).
The Tromboncino mod.28, mounted on the left side of the Moschetto mod.91 for TS (modified) through special inlays in the wood, was supported by a metal frame and had the operating mechanism directly connected to the trigger of the Carbine.
It was loaded by inserting a grenade (created specifically for this project, approximately 72mmx38), into the muzzle of the Tromboncino. Then, the bolt was extracted from the musket, a regular bullet cartridge was manually inserted into the bolt face, and the bolt was inserted into the mobile breech of the Tromboncino (which functioned similarly to the carbine’s breech). At this point, by pressing the rifle’s trigger, the mechanism within the Tromboncino’s sear was activated, the firing pin was released, the shot was fired, and the grenade was then projected forward with the gases released by the ammunition.
However, the cartridge bullet was not projected together with the grenade, but was retained in the chamber and expelled together with the exploded cartridge case.
Each 15-soldier infantry squad was therefore equipped with three Tromboncino mod.28 mounting TS carbines.
Within a short time, it was realized that the grenade initially adopted was not particularly effective: in addition to having a rather erratic trajectory, it often did not explode upon contact with the ground, due to the wrong angle or because it did not release the firing pin correctly.
A new type of ammunition, the SR (later SR2), was adopted around 1930. It was produced by the Società Romana Costruzioni Meccaniche.
This new ammunition was approximately 40mm longer (114mmx38), as it housed a 4-fin stabilizer at its base, useful for facilitating the trajectory and ensuring that the projectile fell exactly head-on, activating the firing pin and detonating the grenade correctly.
In order to correctly house the new ammunition, the Tromboncini mod.28 were modified by shortening the grenade retaining peduncle, which thus went from 62.2mm to 23mm.
The concept of the Tromboncino had a very short life, for several reasons:
- The Tromboncino mod. 28 was bulky, unbalanced, fragile, expensive, inconvenient to load and took away the riflemen’s ability to fire the carbine while using the Tromboncino.
- The Tromboncino had a very short barrel, so the accuracy was more dependent on chance than on a real study with a maximum range of 200 metres.
- The tromboncino couldn’t regulate the gas driven onto the grenade, so the launch was always the same, which could be problematic to make short launches onto enemy trenches, since the trajectory would have been too straight on such short distances.
The Tromboncino mod. 28 already produced were removed from service with the introduction of the mod. 35 “Brixia” light mortar in 45mm, which worked essentially the exact same way, but with a longer barrel, better accuracy, improved explosive charge inside a larger grenade, capable of reaching 500 meters. This was naturally possible because the Brixia 35 did not have to be fired from the shoulder, but was installed on a carriage adequate to manage the recoil and reliability over long distances, managed by a special team.
The 23.000 TS carbines that mounted the Tromboncino mod.28 were dismantled, most of the devices were scrapped and recycled in foundries, while the old stocks, now obsolete, had the empty spaces filled with wooden inlays, and were mainly recycled in other mod. 91 or converted mod.38 carbines.
Courtesy of M. Holmes
“TERNI” PROTOTYPES
TROMBONCINO MOD.28 R
In July 1928 Terni developed this new iteration, with the barrel of the tromboncino and the barrel of the carbine itself pivoting around the center part of the stock, in order to have a single receiver for both devices. Taking back the bolt (the chamber and the bolt lugs were hosted in the barrel itself) and pushing a button you could easily pivot the forward part of the stock around, swapping the main barrel to use.
It kept the same issues of the Mod.28L, so difficult aiming, lack of gas regulator for shorter shots, fragility of the wooden stock.
