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Cold War Yugoslav AT weapons WW2 British AT Weapons WW2 German AT Weapons WW2 Italian AT Weapon WW2 Japanese AT Weapons

Sticky and Magnetic Anti-Tank Weapons

Infantry taking on tanks is a real challenge. Infantrymen are, after all, mainly equipped with weapons primarily intended for killing enemy infantry. Anti-tank guns are large, cumbersome, and heavy and so, right from the first days of the tank in WWI, the goal has been to produce a man-portable anti-tank weapon. One of the first, the Mauser Panzergewehr M1918 was little more than a scaled-up rifle designed to defeat relatively modest armor. More anti-tank rifles followed in the decades afterward up to the first years of WW2, but they all suffered from the same drawbacks. The rifles were so large and heavy they would take at least one (often two) men to carry without being able to carry the usual accouterments of infantry work. On top of this, the performance was relatively modest. Only thinly armored vehicles were vulnerable and anything with armor about 30 mm thick was relatively impervious to them.

Smaller devices, the sort of device which could be issued to a standard soldier making him capable of knocking out a standard enemy tank were, and still are, the gold standard for infantry anti-tank weapons. Grenades, small explosive devices, were useful but were primarily to spray fragments over an area to target infantry. Their effect was relatively limited against armored vehicles unless you could get the explosives in direct contact with the tank and one way to do this was to make the explosive ‘stick’ to the vehicle. Tanks, being made of steel, lent themselves to an obvious thought, why not make the explosive charge magnetic?

Here, there are two distinguishing elements: throwing and placing. Grenades, as throwing weapons, are advantageous for the soldier as they permit the user to maintain a distance from the target. The smaller and lighter (to a point) the grenade, the further it can be thrown. This also means that the features of an effective grenade against armor are also challenged. The size of the charge used is inherently going to be small with larger charges being harder to throw and therefore of shorter range. The next is accuracy, the further an item being thrown, the lesser the chance of hitting the target. Of course, a smaller grenade is also easier to carry and deploy.

A charge, on the other hand, such as an attachable mine, has to be placed on the target. This allows for the significant advantage of a large charge, shaped if possible to optimize anti-armor performance, but which would not lend itself to being thrown. A further advantage of the placed charge is also the obvious one, it guarantees a ‘hit’ because it does not have to be thrown and risk hitting and bouncing off the target. The disadvantages are equally obvious; the man has to expose himself to enemy fire to place the charge, has to be uncomfortably close to the enemy tank, and they are also larger and heavier than a grenade to contain enough explosives to do effective damage, meaning fewer of them can be carried.

All of the various attempts to develop either a hand-placed charge or thrown charge suffered from these problems and none adequately managed to overcome them.

Development

Such a relatively simple idea, though, was far easier to imagine than it was to turn into a functional weapon. Some experience in the area could be drawn from naval warfare. There, a magnetically attached charge had been developed by the British as a means of sabotaging enemy ships: the Limpet mine. A relatively small explosive device, adhering to the steel of a ship’s hull could burst a seam or plate and cause enough damage to put it out of action until it was patched. The power of the charge was magnified if it was placed below the waterline, as the pressure of the water helped to magnify the explosive power of the charge and, obviously, a hole above the waterline was less useful at crippling a ship.

Britain

For the British, the work on the underwater anti-ship charges found its way both in style and name to a land weapon. The ‘Clam’, as it was called, originally came with a light steel body (Mk.I), later replaced with a Bakelite (plastic) body (Mk.II) with four small iron magnets, one in each corner. Resembling a large bar of chocolate, this charge contained a modest charge of just 227 grams of explosive. This charge was a 50:50 mix of Cyclonite and T.N.T. or 55% T.N.T. with 45% Tetryl. Although the device was magnetic, the charge was not shaped nor specifically designed for breaching armor plate. The utility of the mine was for sabotage. Enemy infrastructure, vehicles, railway lines, and storage tanks made excellent targets for this mine. The ‘Clam’ was able to breach just 25 mm of armor, offering little compared to far simpler anti-tank weapons such as the No.82 ‘Gammon’ bomb or No.73 Grenade, aka the ‘Thermos Bomb’. Both of these were weapons that could be thrown from a safe distance, exploded on impact, and were far simpler to make.


The British No. 82 and No. 73 Anti-Tank Grenades. British Explosive Ordnance, 1946

The ‘Clam’, therefore, found a role in sabotage, where it was very effective. Large quantities were produced in Britain and shipped to the Soviet Union for exactly that purpose.

The British ‘Clam’ and Limpet Magnetic charges. The circular Limpet (Mk.III) used a ring of magnets in a flexible fitting allowing for fitting to a contoured surface and capable of breaching 60 mm of steel plate. Source: Wikimedia Commons

The most famous, or infamous, Anti-Tank Grenade is probably the British ‘sticky bomb’. Although not magnetic, the ‘sticky bomb’, officially known as the ‘No.74 S.T. Mk.1 HE’, was constructed from a glass sphere containing 567 grams of nitro-glycerine and covered with a stockinette fabric to which an adhesive was applied. Once the protective steel shells around the grenade had been removed, it could be thrown at an enemy tank. When the bulbous glass ball at the end struck the tank, it would break causing the nitro-glycerine inside to ‘cow-pat’ on the armor and remain stuck there by the glued stockinet until it was detonated. The weapon was not a success, but was also made in large numbers and saw service in North Africa and Italy against German and Italian forces.

The No.74 S.T. Mk.1 HE ‘Sticky Bomb’. Source: British Explosive Ordnance, 1946

Video of a British No.74 Grenade being demonstrated rather badly by American forces in Italy 1944. The thrower did not manage to break the glass bulb, resulting in it falling off before it exploded.

German Weapons

Probably, the most famous magnetic anti-tank device was the German Hafthohlladung (handheld hollow charge). These came in different sizes, although the most common weighed in at 3 kg. This Hafthohlladung mine used three large magnetic feet to adhere to the armor of a vehicle. Each permanent horseshoe-shaped magnetic foot, made from Alnico-type alloy (VDR.546) had an adhesion strength of 6.8 kg-equivalent, meaning over 20 kg of force-equivalent would have to be used to remove a well-adhered mine and also that only a single foot was needed to ‘stick’ the mine to a steel surface. The 3 kg Hafthohlladung contained a simple 1.5 kg shaped charge consisting of PETN/Wax.

A still from a German wartime training film showing the correct method of use of a Hafthohlladung mine against the side of a Soviet T-34 tank. Source: Wikimedia Commons

Placed by hand on the target, the position of the magnets ensured that the shaped charge, when detonated, would strike the armor perpendicularly and at an optimal stand-off distance to maximize its anti-armor potential. According to British tests in 1943, the 3 kg charge could perforate up to 110 mm of I.T. 80 D armor plate or 20 inches of concrete, meaning that it could defeat any Allied tank then in service almost regardless of where it might be placed.

A later, and slightly heavier model of this mine weighing 3.5 kg contained up to 1.7 kg of 40% FpO2 and 60% Hexogen explosive which was capable of defeating over 140 mm of armor. A post-war British report stated that versions of this type of grenade were known in 2, 3, 5, 8, and even 10 kg versions.


3.5 kg bell-shaped variant of the Hafthohlladung, and (right) alongside the conical 3 kg Hafthohlladung. This version used the projectile from the Panzerfaust 30. Source: lexpev.nl

A German soldier in spring 1944 prepares himself for the run out of cover to place a Hafthohlladung on a target either during training or on the Eastern Front. Such a run from cover exposed the user to enemy fire. Source: Bundesarchiv.
An extremely nervous-looking German soldier making a mess of applying a Hafthohlladung against the suspension of a captured French Renault R35 during training. Considering the mine is capable of piercing the armor at any place, it is wholly unclear what he is trying to achieve. Source: Wikimedia Commons

An even larger version of the Hafthohlladung was made for the German Luftwaffe, known as the Panzerhandmine (P.H.M.), or sometimes as the Haft-H (L) ‘Hafthohlladung-Luftwaffe’. This device had the appearance of a small wine bottle with the base cut off to make room for six small magnets. Larger than the Hafthohlladung, the P.H.M.3 still had to be applied by hand.


German Panzerhandmine. Source: TM9-1985-2 German Explosive Ordnance and Intelligence Bulletin May 1945

A small, spiked steel ring was fixed to the bottom of the magnets so that the charge could be stabbed onto a wooden surface too. In order to fasten to a steel surface, all that was required was the removal of this ring. First appearing in about 1942, the P.M.H.3 (a 3 kg version) contained a shaped charge made from 1.06 kg of T.N.T. or a 50:50 Cyclonite/T.N.T. mix. Against a steel target, this charge was sufficient to pierce up to 130 mm, making it a very serious threat against a tank. A 4 kg version (P.H.M.4) was also developed with a performance of up to 150 mm, although details are very limited.

A Hafthohlladung being attached to the back of a tank after having passed over the trench. Showing a Russian soldier, this image illustrates a far safer means of attaching the mine to a tank, obviating the need to stand alongside the vehicle. Even so, the soldier needs a heart of steel to be this close and is still exposed to enemy troops following the tank. Source: Fedoseyev via survincity


German ‘sticky’ shaped charge – the Panzerhandmine S.S.. Details of this version are scarce. Source: Tech. Report No.2/46

A variant of this mine also had a sticky ‘foot’ with different mixtures of explosive compositions. The sticky versions had the advantage of being able to stick to any solid surface regardless of whether it was magnetic or not. In this way, it was emulating the British idea of an adhesive-impregnated fabric behind a thin steel cover. Containing a 205 gram filling of 50% RDX and 50 % TNT, the entire charge weighed just 418 grams, just over a pound. Able to penetrate an I.T. 80 homogenous steel plate 125 mm thick, this small mine was a very effective weapon in terms of penetration although how many were made or used is unknown. A further variation of this grenade allowed it to be thrown, relying on the stickiness to attach to the armor with an instant fuse and small streamer behind to ensure it landed sticky-side down. No other details are known.

Thrown version of the hollow charge German sticky grenade. Source: and Tech. Report No.2/46

Another variation for a hand-placed sticky charge from the Germans was more complex than just an adhesive-impregnated fabric. This version featured the same sort of thin protective cover but with the detonator as part of the sticky process. Here, once the detonator was pulled, it would create an exothermic reaction melting the plastic on the face to make it ‘sticky’. It was, at this point ‘live’, so had to be applied or discarded as it would then blow up. No known use of this particular device or live examples are known.

German handheld Haftmine featured a usual self-melting element allowing it to stick to any hard surface regardless of whether it was magnetic or not. Source: Federoff & Sheffield

One further German magnetic charge was the 3 kg Gebalte Ledung (Eng: Concentrated charge) demolition charge which was little more than a large box with magnetic panels on each side. The interior was filled with cubes of explosives and had the additional advantage of being throwable. Even if the magnets failed to adhere to the steel of the tank, the 3 kg charge was sufficient to cause a lot of damage and possibly cripple the vehicle. However, as it was not a shaped charge, the anti-armor performance was relatively poor. Even so, it was more than capable of knocking out the Soviet T-34 and capable of sticking on the target even when thrown, but few other details were known.

German 3 kg demolition slab ‘Geballte Ladung’ with magnetic plates at each end, fitted with the B.Z.39. Friction Igniter. Source: Department of Tank Design

Many of these German shaped charge devices were made by the firm of Krümmel Fabrik, Dynamite AG which, after a lot of trials, found that the best mix for shaped charges was the explosive Cyclotol which was made up of 60% Cyclonite and 40 % T.N.T. with other mixtures producing less efficient results. Under ideal conditions, they found that a 3 kg shaped charge with this explosive could penetrate up to 250 mm of armor, although ideal conditions were rarely to be found on the battlefield. Either way and despite numerous attempts at both magnetic and ‘sticky’ anti-tank weapons, the Germans did not deploy them in significant numbers. One British report of late 1944 even confirmed that they had, to that point, yet to confirm that even a single Allied tank had been knocked out by a magnetic mine, the far bigger threat being the German ‘bazooka’, the Panzerfaust.

Japan

The Japanese, like the Germans and to a lesser extent, the British, had experimented with magnetic anti-tank weapons. Unlike both of them though, Japan was successful. The primary magnetic anti-tank weapon was the deceptively simple Model 99 Hakobakurai ‘Turtle’ mine. Reminiscent in shape to a turtle with four magnets sticking out like feet and the detonator looking like the head, this canvas-covered circular mine was a potent threat to Allied tanks in the Pacific theater of operations.


Japanese Type 99 Hakobakurai anti-tank mine. Source: TM9-1985-4

Appearing on the battlefield from 1943 onwards, the Hakobakurai weighed just over 1.2 kg and was filled with 0.74 kg of cast blocks of Cyclonite/T.N.T. arranged in a circle. Placed against thin points of armor or on the hatch of a tank, this mine, when detonated, could penetrate 20 mm of steel plate. With one mine on top of another, this could be increased to 30 mm, although, depending on the armor it was on, it could cause damage to a plate thicker than that.

The mine was not a shaped charge and 20 or even 30 mm of armor penetration was not much use against anything but the lightest of Allied tanks deployed against the Japanese, such as the M3 Stuart, unless they were placed in a vulnerable spot such as underneath, on the rear, or over a hatch. However, British testing and examination of these mines reported that, although the penetration was poor, just 20 mm, the shockwave from the blast could scab off the inner face of an armor plate up to 50 mm thick, although the penetration was still limited by it not being a shaped charge. The result also did not include vehicles designed with an inner ‘skin’ either, but the results were still substantial, as it meant that all of the Allied tanks used in the Pacific theatre were vulnerable to these mines depending on where they were placed.

A further development of it, known as the ‘Kyuchake Bakurai’, was rumored and capable of being thrown up to 10 yards (9.1 m), although as of October 1944, no examples were known to have been found.

The Japanese had, from about May 1942, obtained shaped charge technology from the Germans and the results were first recorded by the Americans following combat in New Guinea in August 1944. Here, they reported finding a Japanese shaped charge weapon shaped like a bottle and fitted with a magnetized base, very similar in description of the German Panzerhandmine. As of October 1944 though, the British, aware of this weapon, still had not encountered any:

“Although there are no details of Japanese hollow charge magnetic grenade it is highly probable that such weapons will be encountered soon”
D.T.D. Report M.6411A/4 No.1, October 1944

Scab blasted off from the inside of a 1 ½” (38 mm) thick armor plate by a Japanese Model 99 Hakobakurai ‘Turtle’ mine. Source: Department of Tank Design
Scarring on the outside (left) of a 2” (51 mm) thick armor plate and partially detached scab on the inside (right) caused by the detonation of at least 1 Model 99 mine. Note that the blast has dented the armor and the shape of the individual blocks can even be made out. The gaps between the blocks acted like miniature shaped charges causing these deep scars. Source: Department of Tank Design

Italy

The Kingdom of Italy, perhaps contrary to common ‘knowledge’, also made use of two devices of note. The first of these was a close copy of the British No.74 S.T. Mk.1 HE grenade reproduced from examples captured from the British in North Africa. The Italian version, known as the Model 42 grenade, was manufactured in limited numbers by the firms of Breda and OTO but, importantly, was not sticky. The Italians simply copied the large spherical explosive charge and omitted the not-so-reliable sticky stockinette and glass bulb part of the design. One important note on a heavy grenade like this is the range, just 10-15 meters at best.


The 1 kg Model 42 Grenade contained 574 grams of plastic explosive but was not sticky, it simply emulated the shape of the British No.74. Source: Talpo.it

Although the Model 42 was neither sticky nor magnetic, the Italians did develop probably the most advanced man-portable magnetic anti-tank weapon of all. Here though, there is very little to go off. Just a single photograph is known of the device consisting of a small battery pack and charge on a simple frame. The mine is relatively small, perhaps only 30 cm wide and appears to consist of a bell-shaped central charge, almost certainly a shaped charge with a rectangular battery and two large electromagnets on the ends of the steel frame. Certainly, this would have some advantages as it would not be magnetic all the time, unlike the German Hafthohlladung. It was simply placed on a tank and the switch was flicked to activate the battery and the powerful electro-magnets would hold the charge in place until it detonated. At least one prototype was made in 1943 but, with the collapse of Italy in September 1943, all development is believed to have ceased.

The experimental Italian electromagnetic anti-tank mine. Source: Cappellano and Pignato

Yugoslavia

Perhaps even more obscure than the Italian work on the subject of magnetic weapons is a single known Yugoslavian example. Known as the Mina Prilepka Probojna (Eng: Mine Sticking Puncturing), it was developed after the war and was intended for disabling non-combat and light combat vehicles rather than main battle tanks. It could also be deployed in the manner of the ‘Clam’ for sabotage purposes on infrastructure and consisted of a cylinder with a cone on top containing a 270-gram Hexotol shaped charge and was capable of piercing up to 100 mm of armor plate. Packed 20 to a crate, the MPP was a potent small mine but there is little information available on it in general outside of a small manual of arms. How many were made and whether it was ever used or not is not known.


The Post-War Yugoslavian Mina Prilepka Probojna magnetic mine. Source: Yugoslavian Arms Manual (unknown)

Conclusion

None of the attempts to produce a smaller anti-tank explosive weapon using either sticky or magnetic principles were shown to be effective. The magnetic charges required the soldier to be often suicidally close to the enemy tank. The sticky-option permitted the chance to be further away and possibly have the grenade hopefully strike the vehicle where the charge could perforate the armor. Many other ideas for hand-thrown anti-tank weapons were fielded by various armies in WW2 and thereafter, such as an attempt at a top attack hollow charge similar to that German Panzerhandmine S.S., but none were particularly successful. A short-range, inconsistent effect and a huge question over accuracy were not the reasons these devices do not appear in today’s army’s arsenals though. The answer is that far simpler, more reliable, and more effective systems became available. The German Panzerfaust had, by the end of the war, reached a level of performance where a soldier could be up to 250 meters from a target and perforate up to 200 mm of armor. The modern rocket-propelled grenade (RPG) really embodies this change in military thought for anti-armor weapons and appears in multiple forms for decades, providing an enormous punch for the average soldier against armor.


Examples of when the attack with a magnetic mine has failed. Here wedged into the screen over an air intake (left), and attached to the Schurzen (right) on a StuG III Ausf. G of 2nd Assault Gun Detachment, Bulgarian Army, after combat in Yugoslavia, October 1944. Source: Matev

References

Hills, A. (2020). British Zimmerit: Anti-Magnetic and Camouflage Coatings 1944-1947. FWD Publishing, USA
British Explosive Ordnance, US Department of the Army. June 1946
Federoff, B. & Sheffield, O. (1975). Encyclopedia of Explosives and Related Items Volume 7. US Army Research and Development Command, New Jersey, USA
Fedoseyev, S. Infantry against tanks. Arms and Armour Magazine retrieved from http://survincity.com/2011/11/hand-held-antitank-grenade-since-the-second-world/
Hafthohlladung https://www.lexpev.nl/grenades/europe/germany/hafthohlladung33kilo.html
Technical and Tactical Trends Bulletin No.59, 7th March 1944
TM9-1985-2. (1953). German Explosive Ordnance
Matev, K. (2014). The Armoured Forces of the Bulgarian Army 1936-45. Helion and Company.
Cappellano, F., & Pignato, N. (2008). Andare Contro I Carri Armati. Gaspari Editore
Department of Tank Design. (1944). The Protection of AFVs from Magnetic Grenades
Grenades, mines and boobytraps, retrieved from www.lexpev.nl/grendades/europe/germany/panzerhandmine3magnetic.html
Guardia Nazionale Repubblicana. (1944). Istruzione sulle Bombe a Mano E Loro Impiego
Armaments Design Department. (1946). Technical Report No.2/46 Part N.: German Ammunition – A Survey of Wartime Development – Grenades.

Categories
WW2 Italian AT Weapon

65mm L.17 Mountain Gun

Italy ww2 Kingdom of Italy (1902-1945)
Mountain Gun/Anti-tank Gun – 1,146 Built

Fighting in mountains poses some unique problems for an army. Most crucial amongst these problems is firepower. How do you bring firepower into areas which may only be accessible by rope line? This question is the basis of the mountain gun, a compact weapon able to deliver shells against an enemy force and which can be broken down for transport in multiple loads.

65mm L.17 Model 1913 Mountain gun. Source: Italian Ministry of Defence

Development

Work on a gun to meet the extreme needs of fighting in mountainous terrain began in Italy as far back as 1902 at the Turin Arsenal. This was to be the first gun developed and built completely within Italy for the modern army. The barrel was all steel and, unlike older guns which had to roll back to cope with recoil, this gun had a built-in recoil mechanism. The breech was an interrupted screw type breech.

This design was at the cutting edge of technology when it was conceived and first outlined back in 1902. However, by the time it actually received production orders in 1911, it was still a good gun but not the most modern piece available. Its largest flaw was the lack of elevation, just +20 degrees, meaning that for firing at high elevations troops would have to back the gun onto a ramp. This expedient measure meant that this gun was also envisioned as serving an anti-aircraft role too, though its effectiveness in this role even in WW1 is dubious at best.

Design

The requirements for a mountain gun include that it can be broken down for movement. The 65/17 had a steel barrel on a steel frame with a single fixed tail and carried on wooden spoked wheels with a steel rim. It could be broken into at least 5 (some say 6 pieces – probably due to the optional shield for the gun) for transport by pack mule. In this way, the gun could be towed on a wheeled trailer or pack carried. Ammunition was also pack carried being moved in wooden crates, 2 shells to a box. The gun was light enough to be towed by pack mule, small tracked tractors like the Fiat OCI 708M, motorised tricycles, or even by the soldiers themselves.

Service in Word War 1

Production, like development, was slow. Orders placed in 1911 for this 1902 designed gun were not delivered until 1913. By May 1915, when Italy entered WW1, just 212 guns had been produced. By the end of the fighting in November 1918 a further 685 had been made by both the Turin Arsenal and Naples Army Arsenal, but due to wartime losses the total inventory remaining at the end of WW1 was just 523 guns.

Post WW1

By 1920, the gun was obviously out of date. Despite its good points, the 65 mm gun was insufficient for the needs of the Army and it was replaced by adopting the Skoda 70 mm L13 mountain gun. The Italians had captured large numbers of these guns as Preda Bellica (P.B.). The 65/17 did not disappear from service because of this replacement.

In 1925, an experimental version was trialed with rubber tyres instead of the older wooden and steel ones. The gun shield was smaller and a small limber was available too. In 1926, it was officially reassigned to Infantry units from mountain troops at a rate of 3 guns per regiment and later at 4 guns per regiment.

The colonial troubles in what is now Libya were the next war for the 65/17. Several batteries of guns were sent to fight the insurgency there and, for the first time, the gun was carried on a wheeled vehicle, a Fiat 15ter truck. The gun had already been mounted on tracked vehicles, such as the Fiat 2000, and considered for other vehicles, but this was the first ‘portee’ mounting.
The gun also saw combat in the next Italian war, the war in Ethiopia, and in the Spanish Civil War.

During the Spanish Civil War, in 1936, Italian forces brought with them some 343 guns, some of which were issued to Spanish Nationalist forces. It was during this war that the 65/17 saw its first use as a anti-tank weapon. The relatively weak armor of enemy tanks, like the Soviet supplied T-26, meant that, even with the relatively low muzzle velocity and lack of dedicated anti-tank ammunition, the 65/17 was still an effective anti-tank gun.

Those 343 guns constituted more than half of the available 65/17 guns in Italian inventory but, just as it had been replaced in 1920 for mountain work by the Skoda 70/13, it was replaced in 1935 in infantry use by the Ansaldo 47 mm L32 cannon.

Remaining 65/17 guns were reissued to Guardia alla Frontiera (GaF) and Milizia Volontaria per la Sicurezza Nazionale (MVSN) units and some were even fitted to fixed fortifications. Ammunition was available in large numbers so the guns would always have some use. So much so, in fact, that, despite official replacement and because of losses (either from combat or simple wear and tear) in the Ethiopian and Spanish campaigns, production was actually resumed in 1937, producing 249 new guns.

Despite this reissue and replacement, by 1940 when Italy entered WW2, some regiments were still equipped with this gun.

65/17 dug into a well protected pit in North Africa. This example has the large gun shield fitted. Source: unknown
Captured Morris CS8 with 65/17 fitted in use by Italian forces in Tunisia. Source: Riccio

World War 2

Immediately prior to the Italian entry into WW2, the 65/17 was still in front line infantry service. Some guns had the old wooden wheels with steel rims replaced in 1939 with wheels made from Elekton (Magnesium) fitting with rubber tyres as a weight saving and mobility enhancing measure. By April 1940, just before the declaration of War by Mussolini, there were 700 65/17 guns of various states of repair and upgrade in service with Italian forces. There was still a shortage of anti-tank ammunition however.

As the guns and ammunition (albeit not AT ammunition) was plentiful, it is no surprise that it saw extensive use in WW2 on all of the fronts on which Italy fought. In North Africa, the gun was mounted on Fiat 634 trucks as well as on captured British Morris CS8 trucks forming ‘batterie volanti’ (flying batteries). Mounted on a truck bed, these guns were far more useful than on their old carriages, as they could rotate a full 360 degrees. A total of 28 guns were mounted in this way in 7 batteries of 4.

65/17 gun belonging to the Spezia airborne division in Tunisia being towed by the Guzzi Trialice. Source: Riccio

In Tunisia, the guns saw service with the Spezia airborne division, where they were towed by the Guzzi Trialce (motor-tricycle) formed into 2 batteries of 4 guns. By December 1942, just 444 guns were left in service with the Italians, including those in fixed fortifications. The gun was still in service after the September 1943 armistice too with all parties from partisans to the Germans using them and eight guns being surrendered to the Free French forces in Corsica.

Partisans in a staged photo using a 65/17 with shield in April 1945. Source: Riccio

Ammunition

The 65/17 used a 65mm x 172R round, approximately 4.23 kg in weight. Originally only high explosive ammunition was available for the gun, but was later supplemented with a shrapnel shell and canister shell.

In 1936, an armor piercing (AP) shell (4.23 kg) was produced for the gun but was always in short supply. The gun, despite being completely out of date by 1942, was still in common use and a shaped charge ‘EP’ (effetto pronto – rapid effect) shell was developed which was capable of penetrating up to 120 mm of armor. The range was limited to 6.5 km for HE and 500 meters for AP shells. The rate of fire was between 6 and 12 rounds per minute.

65 mm shells for the 65/17. Left to right: High Explosive, Armor Piercing, EP ‘Effetto Pronto’ (hollow charge), and EPS ‘Effetto Pronto Speciale’ (hollow charge). Source: US Military Intelligence

Conclusion

The 65/17 saw service from 1913 until at least 1945 on all fronts. It fulfilled the role of a mountain gun, infantry gun, tank gun, anti-aircraft gun, anti-tank gun and even a dirigible mounted gun. Ironically the gun was designed for use in terrain and saw its most famous work while mounted expediently onto vehicles for fighting in the mostly flat deserts of North Africa.



Illustration of the 65mm L.17 Mountain Gun produced by Andrie Kirushkin, funded by our Patreon Campaign.

Specifications

Calibre 65mm
Lenght 3.57m overall, barrel 1.15m
Width 1m
Height 1.25m
Weight 556kg
Elevation -7 (also given as -10) to +20
Traverse (on normal mount) 8 degrees
Muzzle velocity 320-355m/s
Range 6.5km (HE), 0.5km (AT)
Ammunition HE, Shrapnel, Canister, AP, EP, EPS
Anti-Armor performance 76mm to 120mm

Sources

Italie1939-45.com
Italian Artillery of WWII, Ralph Riccio
Iron Arm: The Mechanization of Mussolini’s Army, 1920-1940, John Sweet
Gli Autoveicoli da Combattimento Dell’Esercito Italiano V.2, Pignato and Cappellano
TM 9-1985-6 and TO 39B-1A-8 “Italian and French Explosive Ordnance” US Military March 1953
Light Fieldguns, Franz Kosar
Italian Armoured Vehicles of World War Two, Nicola Pignato
La Meccanizzazione dell’Esercito Italiano, Ceva and Curami
motoguzzi.com


Categories
Dutch AT guns Hungarian AT Weapons Swiss AT guns WW2 German AT Weapons WW2 Italian AT Weapon

Solothurn S 18-1000

Switzerland (1939)
Anti-Tank Rifle – around 1,000 produced

The Solothurn S 18-1000 was a Swiss-built 20 mm Anti-Tank rifle which was an upgraded version of the earlier S 18-100. It saw service in both the Axis and Allied forces and was deployed in many theatres of operations through the war. Despite its weight and size, it was appreciated by the troops that used it.

An S 18-154. Source: Sa Kuva

Design and Development

When the Treaty of Versaille was signed on 28th June 1919, the once magnificent German arms industry found itself under considerable restrictions. One of these restrictions was on the development of large caliber weapons capable of taking out tanks, similar to the TankGewehr M1918 developed by Mauser during the First World War.
To bypass these restrictions, Rheinmetall set up a subsidiary in Switzerland in 1929, Waffenfabrik Solothurn. This meant that German engineers could design, test and build weapons without the worry of the victorious Allied powers faulting on Germany for not holding to the Versailles Treaty. In 1930, they had developed the 20×138mmB cartridge or ‘Short Solothurn’, which was one of the most powerful 20 mm rounds in existence at the time and remained in use until the early 1950s. Soon after the development of the 20 mm cartridge, the Solothurn ST-5 anti-aircraft gun was produced and, from here, Solothurn started a journey that saw the development of many weapons, all using the 20 mm Solothurn round. The first foray into anti-tank weapons was the 2 cm Tankbuchse S 5-100 in 1932, which was an offshoot of the ST-5 and was impractical for its intended use, which meant it was not fully developed. In 1933, development started on a more practical anti-tank weapon, the S 18-100. This 44 kg, bull-pup, hard-hitting gun was placed on the export market in 1934 and was soon picked up by Italy, Hungary, and the Netherlands to name but a few.
It was decided in the late 1930s that the S 18-100 series needed a more substantial upgrade (previously the S18-100 saw minor improvements in the S 18-150, S 18-154 and S 18-500). Using the improved 20×138mmB cartridge, also known as the ‘Long Solothurn’, and adding a longer barrel, a ‘harmonica’ style muzzle break, improved action and some other minor modifications, a newer, more hard-hitting version of the Solothurn was created. The weapon worked on a short recoil system, meaning that the barrel moved slightly backward when fired. Because of the large recoil spring, it required a ratchet crank in order to pull the bolt back to set it up for operations. Once the bolt was pulled back, a magazine could then be loaded. When fired, the barrel recoiled, moving the attached rotary bolt and unlocking the bolt which then ejected the spent casing. The bolt is then driven forward by the large spring, loading a fresh cartridge from the magazine. Like many anti-tank rifles of the time, it came with an integrated bipod, which allowed for some recoil absorption, and a single adjustable monopod to the rear just ahead of the cushioned butt plate. These modifications increased the weight from a substantial 45 kg to a hefty 53 kg and saw Solothurn develop the SO9 carriage for it. This was a simple two-wheeled carriage which had space for two ammunition boxes and allowed for free traverse. It also had the ability to change the elevation through a screw. The split trails could be flipped forward and locked together to allow the gun team to move the gun with ease to a new position.

A brochure picture of a Swiss soldier firing an S 18-1000 on the SO 9 carriage. Source:- Axishistory
During Solothurn’s trials in 1939, it performed quite respectfully. The much improved ‘Long Solothurn’ round coupled with the 144.78mm (57 inch) long barrel gave it a muzzle velocity of 910 m/s and could penetrate 35 mm of armor plate at 300 meters.

On the Market

After trials, Solothurn approved the S 18-1000 for production. The design of the weapon, alongside its impressive performance, saw it gain a lot of attraction on the international market.

A fully kitted out S 18-1000. Source:- MurphyAuctions
The first nation to acquire the S 18-1000 for service was the Swiss Army, which placed an initial order for 60. These were designated Tankbüchse Solo 40 and were delivered in the first quarter of 1940. Another 33 were ordered as the Swiss Army was impressed by its capabilities, bringing the total in Swiss use to 93. One rifle was installed to the prototype Type 41 Patrol Boat Uri.
The Netherlands had bought six S 18-15 in 1937 for trials but rejected them upon seeing the initial results for the S18-1000. A definitive order for 662 S18-1000s was placed in late 1938, divided as 340 for the Royal Netherlands Army (Koninklijke Landmacht) and 322 for the Royal Netherlands East Indies Army (Koninklijk Nederlands Indisch Leger; KNIL). By the time of the German invasion in May 1940, 125 Dutch Army and 72 KNIL rifles had been delivered.
The Italians also looked at the S 18-1000 after rejecting the S 18-100 in 1934. They placed initial orders in 1939 for trials and the first pieces arrived in early 1940 being designated Carabina “S”. At the conclusion of the trials, the Italian Royal Army (Regio Esercito) wanted to equip every infantry battalion with 6 pieces. It is unknown how many were delivered to the Italians, but it is thought to be around 578 of the estimated 1,131 required. The main reason for the lack of deliveries was that Switzerland was placing restrictions on the exportation of war materials to any belligerent nation in 1940.
With Europe being engulfed by war, Sweden started to look towards protecting itself. In 1940, it made inquiries to purchase 480 S 18-1000s. These were approved as Sweden was a neutral country and thus not subjected to Switzerland’s restrictions. Using balance of trade payments with Germany for steel, the rifles arrived between 1940-1941 and were designated 20 mm pansarvärnskanon m/1939.
Hungary had purchased the S 18-100 in 1935 and were producing their own licensed variant, the 36M 20mm Nehézpuska. After the Slovak–Hungarian War, they realized that the 36M was in need of upgrading and purchased around 50 (sources vary) of the new S 18-1000 in early 1940, but as restrictions became tighter, they were unable to purchase more and so production continued on the 36M until 1943.
The US Army had concluded in the mid-1930s that the .50 M2 Heavy Barrel (HB) machine gun would be adopted as the official light anti-tank gun and general vehicle-mounted machine gun. However, observations made during the Spanish Civil War suggested that the .50 might not be sufficient in future conflicts as an anti-tank weapon, so work was put towards creating an anti-tank gun, the 37 mm Gun M3. While the infantry branch championed such a move, the cavalry branch and US Marine Corps still expressed interest in a light anti-mechanization weapon. To this end, the Ordnance Department ordered two S 18-100 rifles in 1939, along with 2,000 rounds of ammunition for trails by the Infantry and Cavalry Boards at the Aberdeen Proving Grounds. The results of the trials were unsatisfactory, but as the trials were coming to a close, the S 18-1000 was ready, and so, an example was obtained for testing. Arriving in April 1940, it performed better than its predecessor and was passed on for further trials by both the Infantry and Cavalry boards. The S 18-1000 was seen as superior in performance to the M2 machine gun, so an order was placed with Solothurn for a further 50 models with 50,000 rounds of ammunition which would be standardized as the 20 mm Automatic Gun T3. During negotiations with Solothurn though, things turned difficult. This was down to Solothurn’s parent company – Rheinmetall – specifically forbidding the sale of Solothurn’s anti-tank rifles to any country without its approval, and so, the acquisition was abandoned.

A picture showing the US Army trial of the Solothurn at Aberdeen Proving Ground on 9 April 1940. Source: Reddit
Finland was attempting to modernize its military inventory in the run-up to the Winter War of November 1939. As part of this, one S 18-1000 was purchased by the Puolustusministeriö (Ministry of Defence) in August 1939 (one of the first models as it had the serial number of 4 stamped upon it) for testing. Unfortunately, though, any chance of purchasing more was rendered difficult due to the Soviet-German Molotov-Ribbentrop Pact which saw Germany restrict arms shipments to Finland through its territory.

Swedish presentation of the Solothurn S18-1000 (or 20 mm pkvan m/39) with characteristics

Solothurn at War

When the German military crossed the Polish border on the morning of 1st September 1939, the nations of Europe realized that another great war was unavoidable. The armies mobilized against the threats and so the Solothurn S 18-1000 was to be put to the test.
After Poland fell to the joint German-Soviet invasion, the world expected a bloodbath in the West between the Anglo-French alliance and Germany, but outside a few skirmishes on the border nothing occurred for eight months in what became known as the ‘Phoney War’.
It is not known if the single S 18-1000 that Finland acquired before the outbreak of the Winter War was ever issued to combat troops and so it is thought that the S 18-1000s baptism of fire occurred during the German invasion of the Netherlands. The Germans launched their offensive against the Western allies on the morning of 10th May 1940. The 4th Panzer Division was given orders to secure the strategically important Dutch city of Maastricht. The city contained vital bridges over the Maas River, as well as sat to the north of the Belgian Fort Eben-Emael. The Dutch had been on alert since 7th May and troops had been deployed to areas the General Staff felt were vital to the German line of attack. Sergeant Van der Sande was in command of an anti-tank rifle section containing two S 18-1000s and was ordered to deploy his weapons near the two bridges of Wilhelminabrug and Sint Servaasbrug and delay any German advance. At 05:15 on the morning of the 10th May, the first German vehicles were spotted by der Sande’s section and the two anti-tank gunners, Rietveld and Plusjé, prepared their weapons. The order to fire was given and within minutes 2 armored cars were out of action and a third was severely crippled. The Germans reacted by bringing up a 37 mm anti-tank gun and firing at the defensive position forcing the surviving Dutchmen to retreat across the river. The action helped delay the German vanguard enough that the two bridges were blown at 06:00.
Sergeant Sande and his men were not the only group of Dutchmen with Solothurns that were doing their part to delay the advance. A kilometer north of the Wilhelminabrug Bridge was the railway bridge and another strategic objective for the Germans. A platoon of 35 Dutch soldiers, with a pair of Solothurns, held their position against a mainly infantry assault. Soon the lieutenant ordered a withdrawal across the bridge and within moments the bridge was blown. However, the action did not stop there. The German infantry force soon received reinforcements and attempted to secure the bridge in order to effect repairs. Two armored cars attempted to cross the river but were destroyed by the Solothurns. A Panzer I was also disabled as it went to the edge of the riverbank to provide suppressive fire. The fighting became intense and more armor was brought forward, including a handful of Panzerjäger I tank destroyers (two were subsequently knocked out by the anti-tank rifles) and soon the Dutch found themselves overwhelmed. The Battle of Maastricht ended in the early afternoon with a ceasefire, but despite the Dutch loosing, their bravery and the hard-hitting power of the Solothurns accounted for several German AFVs.
The German Army is known to have acquired a number of Solothurn S-18 rifles, including the 1000 model, and deployed them alongside their own anti-tank rifles. What is not know is exactly how many or their exact deployment. The table of organization and equipment for a German Infantry division in 1940 put the complement of ATRs at 108 per Infantry Division with each of the 36 Rifle Companies containing an anti-tank rifle section of 3 rifles, the most numerous being the Panzerbüchse 39. Against the main French tanks, Hotchkiss H35 and Renault R35, any anti-tank rifle would be effectively useless except at extremely close ranges.

An S 18-1000 mounted on an Sd.Kfz. 250. Source: Reddit

A propaganda picture of Italian Bersaglieri manning a “36M Fucile Contracarro da 20-mm Solothurn” in the North African desert. Source: Axishistory
The next known usages of the Solothurn S 18-1000 was by the Italians in the Desert Campaign. Italy received its first batch of 100 Solothurn S 18-1000s in late 1940 and immediately shipped them to their troops serving in the African desert. It was intended to arm every Italian division with an anti-tank company that contained 3 platoons of 4 Solothurns each, but this was not possible, so the S 18-1000s were given to elite units like the Bersaglieri (an Italian light infantry unit) and Compagnie Auto-Avio-Sahariane (Auto-Saharan Companies, long range desert units). More Solothurns started to arrive at the end of 1941/early 1942 and were assigned on the basis of 9 per Bersaglieri to fit in with their intended role as light infantry. The hard-hitting power, coupled with their small silhouette, meant that the weapon could be effectively used against the Commonwealth forces and their lightly armored tanks such as the Light Tank Mk.VI and Cruiser Mk.IV. The weapon also became popular with the Compagnie Auto-Avio-Sahariane, or Auto-Saharan Companies, which were the Italian version of the British Long Range Desert Group (LRDG). When the Camionetta Desertica SPA-Viberti AS.42 arrived in September 1942, several were equipped with the S 18-1000 to help in the company’s mission of hunting down the LRDG. In this role, the S 18-1000 succeeded, as the LRDG operated in similarly open-topped and lightly armored four-wheel vehicles.

An AS.42 somewhere in the Libyan desert, 1942. Source:- tapatalk.com
Another Italian use of the S 18-1000 that is often forgotten is the L3 cc (controcarro or anti-tank). Using the Carro Veloce L3/35 light tank as a base, the twin 8mm Bredas were replaced with the Solothurn. An exact number of how many were produced is not known, but it was not many and they arrived in Libya in late 1942. They performed adequately in the Axis retreat through Africa and some participated in the famous Battle of Kasserine Pass.

An abandoned L3 cc. Source:- tapatalk.com
As the weapon was deployed to Italian frontline units in Africa, it was inevitable that some would fall into the hands of the Commonwealth forces they were fighting against. The Australian 2/2nd Anti-Tank Regiment had one of its reserve batteries equipped with a number of captured Solothurns during the Syria–Lebanon Campaign. How widespread it was among other Commonwealth units is not known, but it can be speculated that several Solothurns would have been repurposed.
It is also alleged that some S 18-1000s of the Royal Netherlands East Indies Army fell into the hands of the Imperial Japanese Army who found them more reliable and effective than their own Type 97 anti-tank rifle and used them until they ran out of ammunition.

End of Life

With the rifle weighing 53.5 kg/118 lb empty (54.7 kg/120.6 lb with 10 round magazine attached), as well as the increasing amount of armor being put onto AFV, it meant that the Solothurn was losing its place on the battlefield. As the war raged on the Solothurn was seen less and less and it is believed that the last combat uses of the S 18-1000 were by Italian forces of the National Republican Army as they fought frantically against the Allied advance. A select fire version was produced in 1942, designated the S 18-1100 ‘Universalwaffe’ (universal weapon) and was sold with a specialized AA mount (SO 11) to be able to engage aircraft, as well as the SO 9 carriage for use against AFVs. Not many, a few hundred, of these were produced until production was stopped at the end of 1942/early 1943.

The S 18-1100 on the SO 11 carriage from a Solothurn brochure. Source:- Axishistory
After the war, hundreds of S 18-1000s were put into the lucrative US gun market where they were sold off to gun collectors and enthusiasts. Today it is a rare find but there is still a number of them in the hands of collectors and occasionally they may be found upon the firing ranges.

A post-war advert with an embellished background of the S18-1000. Source:- 2cm flak

Conclusion

Anti-Tank Rifles are often confused with Anti-Tank Guns, both in nomenclature and usage. ATRs are designed to allow the standard infantry unit to disable armored fighting vehicles and work in conjunction with other weapons, like dedicated anti-tank guns. When ATRs were developed during the interwar period, they were effective if albeit bulky but they offered a cheap and more mobile alternative than anti-tank artillery.
The Solothurn S 18-1000 could be called the pinnacle of anti-tank rifles. The ‘Long Solothurn’ round allowed it to keep up with armored development until 1942 but it quickly dropped off when the Allies started to deploy vehicles like the M3 Grant/Lee and M4 Sherman medium tanks in large numbers. The two biggest drawbacks to the S 18-1000 were its weight and its complicated system which meant that misuse or lack of attention could damage the weapon easily. With the heavy deployment of shaped charges and rocket-propelled grenades in 1943, the infantry now had a more effective and lightweight anti-tank weapon that was more viable than the ATRs of the previous few years. The Solothurn, along with its brothers, were forced in obsolescence and became curiosities.

Sources

Zaloga, Steven. The Anti-Tank Rifle, Osprey Publishing, 2018
Weeks, John. Men Against Tanks: History of Anti-tank Warfare, David & Charles, 1975
Axishistory.com
Forgottenweapons.com



Illustration of the Solothurn S 18-1000 made by Yuvnashva Sharma. Funded by our Patreon campaign.

Tanks Encyclopedia Magazine, #3

Tanks Encyclopedia Magazine, #1 Republished

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Categories
AT weapons WW2 Italian AT Weapon

60mm Lanciabombe

Italian armour ww2 Kingdom of Italy (1943-45)
Experimental Anti-Tank Weapon – 1 Built

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Sketch plan of prototype anti-tank weapon. Source: Report 311

Desperate Times

When nations have their backs against the wall and are facing a fight for their existence, there tends to be an abundance of rather unusual weapons. Some of the weapons developed by the Home Guard in Great Britain in the Second World War, like the Northover projector, are good examples of this. Italy, with a long tradition of firearms manufacture, was no different and already had extensive experience with grenade firing and small mortars. In 1943 though, their mainland had been invaded by the Allies as they had already lost control of the island of Sicily. Tank production was in a poor state and the Allies’ superiority with tanks left a very bleak outlook for the Kingdom of Italy in the War. An expedient anti-tank weapon was called for.
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Carcano Model 91/24 T.S. The exact variant used is not known. Source: candrsenal.com

Development

The call for this expedient and simple anti-tank weapon came from the Ministry for War prior to the armistice of the 8th September 1943. It was to combine parts from a mortar and a carbine fitted together to form a rather crude, very large caliber gun firing a shaped charge shell. The Italians had already produced a production model carbine with an attached grenade launcher which used a bullet capture system as far back as 1928. This was along very similar lines to the new requested weapon and may have served as some of the inspiration behind it. The Technical Section of the Ministry for War had already made some preliminary experiments prior to September 1943 and the results were promising.
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Model 1928 Tromboncino grenade launcher (both with bolt in carbine and with bolt in grenade launcher) based on the Model 91/28 carbine. Source: modernfirearms.net
The weapon was given the go-ahead but, by the time of the armistice, only a single experimental prototype had actually been constructed, although performance trials were underway by September 1943.
With just this one prototype constructed by the time of the armistice, the unidentified Italian officer in charge of the project hid the weapon and all of the paperwork associated with it, to prevent it from falling into the hands of the Germans.
When the Allies entered Rome in June 1944 this hidden secret weapon and associated paperwork was removed from its hiding place and taken by the Italian officer to the US Army G-2 Headquarters in Rome (APO 794).
The weapon was examined by Major Russell Fisher and the design was closely discussed between him and the Italian officer who even offered to demonstrate the weapon, as he claimed to have fired the weapon many times, from a standing position without difficulty. This offer though was not carried out.
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Compact CEMSA 63.5mm L25.5 mortar which may have been the origin of the barrel. This weapon could throw a 2kg shell well over 300m. Source: CEMSA

Design of the Weapon

The experimental model was, like most prototypes, rather crude. It was made by means of a redundant 60mm mortar tube and a cut down stock from a carbine fastened together. The 60mm shell was propelled from the barrel by means of a black powder cartridge inserted into the breech of the carbine under the barrel.
The drawings do not appear to show any variation from the original magazine or firing mechanism of the Model 91 rifle and therefore it is believed it would use the same 6.5x52mm cartridge.
Upon a pull of the trigger, this blank round was fired in the manner of a normal bullet except that the explosive gases upon leaving the very short barrel, instead of propelling a bullet, were directed into a large expansion chamber under the mortar barrel and then directed to the mortar round. Just like the smaller Brixia mortar, this weapon was fired by means of a magazine fed blank cartridge and a rapid rate of fire would be able to be obtained. Reloading would be by the simple means of putting a new shell into the barrel at the muzzle and then cycling the bolt action of the rifle to chamber a new blank cartridge. The rifle had a six-round clip inside and, assuming these blank rounds simply replaced the old live rounds, only shells would have to be loaded for the first six rounds.

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Rifle calibre blank cartridge containing the 1.9 grams of ballistite propellant. Source: Report 311

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Example of the type of blank initiator round used. This example is for the 45mm Brixia mortar. Source: not known

Propulsion System

The expanding gasses released from the combustion of the 1.9 grams of ballistite in the blank cartridge were directed into the expansion chamber. This chamber was connected by two short barrels backward (towards the firer) and into the breach of the 60mm mortar tube. This unusual mechanism had the disadvantage that not all of the propulsive force of the black powder charge was directed to the mortar round. A lot of energy was lost. It had a significant advantage, however, that the pressure rise in the barrel was very even, permitting a consistent rise in pressure for the propulsion of the shell. The interview with the Italian officer yielded information that, over the course of its short development, various expansion chamber sizes were tested out in order to achieve the required balance in the pressure gradient within the weapon.

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Detail of gas porting system to move gas from expansion chamber to the rear of the barrel. Source: Report 311


Illustration of the 60mm Lanciabombe by Andrei “Octo” Kirushkin and paid for with funds from our Patreon campaign.

Recoil Management

Recoil was managed in two ways. The first was a very simple spring loaded mechanism in the buttstock of the weapon cushioning the shoulder of the firer. The second part of the recoil management was more complicated, far too complicated for a weapon meant to be an expedient design. This system consisted of a slide onto which the main barrel was mounted. This slide permitted the barrel to move backward and this motion was dampened by means of a spring.
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Details of sprung shoulder pad as part of recoil management. Source: Report 311

The Shell

The shell itself was very similar to the rather small 45mm Brixia mortar shell and was a short shell just under 30cm long with a rounded nose. The explosive body containing the charge was attached to an aluminum tail section with eight fins approximately 12cm long. This 60mm round weighed just 0.85kg and contained 370 grams of T4 (trimethyl trinitro amine). The explosives were arranged around an inner cone made from steel and a hollow front section. The rounded nose was a simple cap made from steel. The charge was detonated upon striking a hard target by means of an instantaneous fuze in the base of the projectile. This was the same type of fuze used in the Brixia mortar, although work on an armor-piercing shell for the Brixia was discontinued by 1941. The fuze would therefore almost certainly be of an all-aluminum construction like the Brixia M.1939 fuze.
The propelling gases could throw this small shell accurately out to a range of 80 meters in a flat trajectory and when fired in a high arc a maximum bombarding range of 250 meters. Armor penetration was by means of the shaped charge and was found to be able to defeat up to 70mm of armor on a test target consisting of plates of 30 and 40mm thick armor.
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60mm hollow charge shell. Source: Report 311

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60mm HEAT round for the weapon. Source: Modified by author to illustrate explosive filler

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Cross section of the 45mm Brixia shell showing fize system. Source: US Military Manual of enemy ammunition

Conclusion

The weapon never reached production status and the war had already progressed well past the point where even if it had been in mass production it would have made any effective difference. The war for the Axis was lost and this weapon was just one of innumerable lost prototypes and projects. It had no effect on the war but was a novel solution to the problem of a shoulder-fired anti-tank weapon. The current location of this weapon handed to the Americans in 1944 is not known.
Specifications:
Calibre: 60mm
Length:
Weight: 7.8kg (unloaded)
Weight of shell: 0.85kg
Weight of explosives: 0.37kg
Anti-armor performance: 70mm
Range: up to 250 meters
Muzzle velocity: 60m/s

Links, Resources & Further Reading

Report 311 ‘Italian Anti-Tank Shoulder Weapon’, Major R. Fisher, US Army, Department of Commerce, 5th December 1944
Andare Contro i Carri Armati, Cappellano and Pignato
https://candrsenal.com
CEMSA 63.5mm Mortar Manual
War Office Pamphlet No.4 Handbook of Enemy Ammunition 1940
Unnamed US Military Manual on enemy ammunition circa 1942
Modern Firearms.net https://modernfirearms.net/en/grenade-launchers/italy-grenade-launchers/tromboncino-m28-eng/

Forgotten Weapons video of the Modello 1928 Tromboncino Grenade Launcher