A recoilless rifle, recoilless launcher or recoilless gun, sometimes abbreviated "RR" or "RCL" (for ReCoilLess) is a type of lightweight artillery system or man-portable launcher that is designed to eject some form of countermass such as propellant gas from the rear of the weapon at the moment of firing, creating forward thrust that counteracts most of the weapon's recoil. This allows for the elimination of much of the heavy and bulky recoil-counteracting equipment of a conventional cannon as well as a thinner-walled barrel, and thus the launch of a relatively large projectile from a platform that would not be capable of handling the weight or recoil of a conventional gun of the same size. Technically, only devices that use spin-stabilized projectiles fired from a rifled barrel are recoilless rifles, while smoothbore variants (which can be fin-stabilized or unstabilized) are recoilless guns. This distinction is often lost, and both are often called recoilless rifles.
Though similar in appearance to a tube-based rocket launcher (since these also operate on a recoilless launch principle), a recoilless weapon fires shells that use conventional gun propellant. The key difference from rocket launchers (whether man-portable or not) is that the projectile of the recoilless rifle or gun is initially launched using conventional explosive propellant rather than a rocket motor. While there are rocket-assisted rounds for recoilless launchers, they are still ejected from the barrel by the detonation of an initial explosive propelling charge.
Because some projectile velocity is inevitably lost to the recoil compensation, recoilless rifles tend to have inferior range to traditional cannons, although with a far greater ease of transport, making them popular with paratroop, mountain warfare and special forces units, where portability is of particular concern, as well as with some light infantry and infantry fire support units. The greatly diminished recoil allows for devices that can be carried by individual infantrymen: heavier recoilless rifles are mounted on light tripods, wheeled light carriages, or small vehicles, and intended to be carried by crew of two to five. The largest versions retain enough bulk and recoil to be restricted to a towed mount or relatively heavy vehicle, but are still much lighter and more portable than cannons of the same scale. Such large systems have mostly been replaced by guided anti-tank missiles in first-world armies.
There are a number of principles under which a recoilless gun can operate, all involving the ejection of some kind of counter-mass from the rear of the gun tube to offset the force of the projectile being fired forward. The most basic method, and the first to be employed, is simply making a double-ended gun with a conventional sealed breech, which fires identical projectiles forwards and backwards. Such a system places enormous stress on its midpoint, is extremely cumbersome to reload, and has the highly undesirable effect of launching a projectile potentially just as deadly as the one launched at the enemy at a point behind the shooter where their allies may well be.
The most common system involves venting some portion of the weapon's propellant gas to the rear of the tube, in the same fashion as a rocket launcher. This creates a forward directed momentum which is nearly equal to the rearward momentum (recoil) imparted to the system by accelerating the projectile. The balance thus created does not leave much momentum to be imparted to the weapon's mounting or the gunner in the form of felt recoil. Since recoil has been mostly negated, a heavy and complex recoil damping mechanism is not necessary. Despite the name, it is rare for the forces to completely balance, and real-world recoilless rifles do recoil noticeably (with varying degrees of severity). Recoilless rifles will not function correctly if the venting system is damaged, blocked, or poorly maintained: in this state, the recoil-damping effect can be reduced or lost altogether, leading to dangerously powerful recoil. Conversely, if a projectile becomes lodged in the barrel for any reason, the entire weapon will be forced forward.
Recoilless rifle rounds for breech-loading reloadable systems resemble conventional cased ammunition, using a driving band to engage the rifled gun tube and spin-stabilize the projectile. The casing of a recoilless rifle round is often perforated to vent the propellant gases, which are then directed to the rear by an expansion chamber surrounding the weapon's breech. In the case of single-shot recoilless weapons such as the Panzerfaust or AT4, the device is externally almost identical in design to a single-shot rocket launcher: the key difference is that the launch tube is a gun that launches the projectile using a pre-loaded powder charge, not a hollow tube. Weapons of this type can either encase their projectile inside the disposable gun tube, or mount it on the muzzle: the latter allows the launching of an above-caliber projectile. Like single shot rocket launchers, the need to only survive a single firing means that single-shot recoilless weapons can be made from relatively flimsy and therefore very light materials, such as fiberglass. Recoilless gun launch systems are often used to provide the initial thrust for man-portable weapons firing rocket-powered projectiles: examples include the RPG-7, Panzerfaust 3 and MATADOR.
Since venting propellant gases to the rear can be dangerous in confined spaces, some recoilless guns use a combination of a countershot and captive piston propelling cartridge design to avoid both recoil and backblast. The Armbrust "cartridge," for example, contains the propellant charge inside a double-ended piston assembly, with the projectile in front, and an equal countermass of shredded plastic to the rear. On firing, the propellant expands rapidly, pushing the pistons outward. This pushes the projectile forwards towards the target and the countermass backwards providing the recoilless effect. The shredded plastic countermass is quickly slowed by air resistance and is harmless at a distance more than a few feet from the rear of the barrel. The two ends of the piston assembly are captured at the ends of the barrel, by which point the propellant gas has expanded and cooled enough that there is no threat of explosion. Other countermass materials that have been used include inert powders and liquids.
The first recoilless gun was developed by Commander Cleland Davis of the US Navy, just prior to World War I. His design, named the Davis gun, connected two guns back-to-back, with the backwards-facing gun loaded with lead balls and grease of the same weight as the shell in the other gun. His idea was used experimentally by the British as an anti-Zeppelin and anti-submarine weapon mounted on a Handley Page O/100 bomber and intended to be installed on other aircraft.
In the Soviet Union, the development of recoilless weapons ("Dinamo-Reaktivnaya Pushka" (DRP), roughly "dynamic reaction cannon") began in 1923. In the 1930s, many different types of weapons were built and tested with configurations ranging from 37 mm to 305 mm. Some of the smaller examples were tested in aircraft (Grigorovich I-Z and Tupolev I-12) and saw some limited production and service, but development was abandoned around 1938. The best-known of these early recoilless rifles was the Model 1935 76 mm DRP designed by Leonid Kurchevsky. A small number of these mounted on trucks saw combat in the Winter War. Two were captured by the Finns and tested; one example was given to the Germans in 1940.
The first recoilless gun to enter service in Germany was the 7.5 cm Leichtgeschütz 40 ("light gun" '40), a simple 75 mm smoothbore recoilless gun developed to give German airborne troops artillery and anti-tank support that could be parachuted into battle. The 7.5cm LG 40 was found to be so useful during the invasion of Crete that Krupp and Rheinmetall set to work creating more powerful versions, respectively the 10.5 cm Leichtgeschütz 40 and 10.5 cm Leichtgeschütz 42. These weapons were loosely copied by the US Army. The Luftwaffe also showed great interest in aircraft-mounted recoilless weapons to allow their planes to attack tanks, fortified structures and ships. These included the unusual Düsenkanone 88, an 88mm recoilless rifle fed by a 10-round rotary cylinder and with the exhaust vent angled upwards at 51 degrees to the barrel so it could pass through the host aircraft's fuselage rather than risking a rear-vented backblast damaging the tail, and the Sondergerät SG104 "Münchhausen", a gargantuan 14-inch (355.6mm) weapon designed to be mounted under the fuselage of a Dornier Do 217. None of these systems proceeded beyond the prototype stage.
The US did have a development program, and it is not clear to what extent the German designs were copied. These weapons remained fairly rare during the war, although the American M20 became increasingly common in 1945. Postwar saw a great deal of interest in recoilless systems, as they potentially offered an effective replacement for the obsolete anti-tank rifle in infantry units.
During World War II, the Swedish military developed a shoulder-fired 20 mm device, the Pansarvärnsgevär m/42 (20 mm m/42); the British expressed their interest in it, but by that point the weapon, patterned after obsolete anti-tank rifles, was too weak to be effective against period tank armor. This system would form the basis of the much more successful Carl Gustav recoilless rifle postwar.
By the time of the Korean War, recoilless rifles were found throughout the US forces. The earliest American infantry recoilless rifles were the shoulder-fired 57 mm M18 and the tripod-mounted 75 mm M20, later followed by the 105 mm M27: the latter proved unreliable, too heavy, and too hard to aim. Newer models replacing these were the 90 mm M67 and 106 mm M40 (which was actually 105 mm caliber, but designated otherwise to prevent accidental issue of incompatible M27 ammunition). In addition, the Davy Crockett, a muzzle-loaded recoilless launch system for tactical nuclear warheads intended to counteract Soviet tank units, was development in the 1960s and deployed to American units in Germany.
The Soviet Union adopted a series of crew-served smoothbore recoilless guns in the 1950s and 1960s, specifically the 73mm SPG-9, 82mm B-10 and 107mm B-11. All are found quite commonly around the world in the inventories of former Soviet client states, where they are usually used as anti-tank guns.
The British, whose efforts were led by Charles Dennistoun Burney, inventor of the Wallbuster HESH round, also developed recoilless designs. Burney demonstrated the technique with a recoilless 4-gauge shotgun. His "Burney Gun" was developed to fire the Wallbuster shell against the Atlantic Wall defences, but was not required in the D-Day landings of 1944. He went on to produce further designs, with two in particular created as anti-tank weapons. The Ordnance, RCL, 3.45 in could be fired off a man's shoulder or from a light tripod, and fired an 11 lb (5 kg) wallbuster shell to 1,000 yards. The larger Ordnance RCL. 3.7in fired a 22.2 lb (10 kg) wallbuster to 2,000 yards. Postwar work developed and deployed the BAT (Battalion, Anti Tank) series of recoilless rifles, culminating in the 120 mm L6 WOMBAT. This was too large to be transported by infantry and was usually towed by jeep. The weapon was aimed via a spotting rifle, a modified Bren Gun on the MOBAT and an American M8C spotting rifle on the WOMBAT: the latter fired a .50 BAT (12.7x77mm) point-detonating incendiary tracer round whose trajectory matched that of the main weapon. When tracer rounds hits were observed, the main gun was fired.
During the late 1960s and 1970s, SACLOS wire-guided missiles began to supplant recoilless rifles in the anti-tank role. While recoilless rifles retain several advantages such as being able to be employed at extremely close range, while a guided missile typically has a significant deadzone before it can arm and begin to seek its target, missile systems were lighter and more accurate, and were better suited to deployment of hollow-charge warheads. The large crew-served recoilless rifle started to disappear from first-rate armed forces, except in areas such as the Arctic, where thermal batteries used to provide after-launch power to wire-guided missiles like M47 Dragon and BGM-71 TOW would fail due to extremely low temperatures. The former 6th Light Infantry Division in Alaska used the M67 in its special weapons platoons, as did the Ranger Battalions and the US Army's Berlin Brigade. The last major use was the M50 Ontos, which mounted six M40 rifles on a light (9 ton) tracked chassis. They were largely used in an anti-personnel role firing "beehive" flechette rounds. In 1970 the Ontos was removed from service and most were broken up. The M40, usually mounted on a jeep or technical, is still very common in conflict zones throughout the world, where it is used as a hard-hitting strike weapon in support of infantry, with the M40-armed technical fulfilling a similar combat role to an attack helicopter.
Front-line recoilless weapons in the armies of modern industrialized nations are mostly man-portable devices such as the Carl Gustav, an 84 mm weapon. First introduced in 1948 and exported extensively since 1964, it is still in widespread use throughout the world today: a huge selection of special-purpose rounds are available for the system, and the current variant, known as the M4 or M3E1, is designed to be compatible with computerized optics and future "smart" ammunition. Many nations also use a weapon derived from the Carl Gustav, the one-shot AT4, which was originally developed in 1984 to fulfil an urgent requirement for an effective replacement for the M72 LAW after the failure of the FGR-17 Viper program the previous year. The ubiquitous RPG-7 is also technically a recoilless gun, since its rocket-powered projectile is launched using an explosive booster charge (even more so when firing the OG-7V anti-personnel round, which has no rocket motor), though it is usually not classified as one.
Obsolete 75mm M20 and 105mm M27 recoilless rifles were used by the U.S. National Park Service and the U.S. Forest Service as a system for triggering controlled avalanches at a safe distance, from the early 1950s until the US Military's inventory of surplus ammunition for these weapons was exhausted in the 1990s. They were then replaced with M40 106mm recoilless rifles, but following a catastrophic in-bore ammunition explosion that killed one of the five-man gun crew at Alpine Meadows Ski Resort, California in 1995 and two further in-bore explosions at Mammoth Mountain, California within thirteen days of each other in December 2002, all such guns were removed from use and replaced with surplus 105mm howitzers.
The L2 BAT (Battalion, Anti-Tank) was a 120 mm calibre recoilless anti-tank rifle used by the British Army. It was also produced in the MOBAT version without a gun shield, and the ConBAT version with a new spotting rifle attachment. The L6 Wombat version was greatly lightened through the use of magnesium alloys. The Wombat was used by mobile units such as paratroopers and marines.BAT was developed from the wartime Ordnance, RCL, 3.45 in, replacing it and the Ordnance QF 17-pounder to become the standard anti-tank weapon of the Army in the post-World War II era. The BAT and MOBAT were used until anti-tank guided missiles, such as Vigilant and MILAN, took their place. WOMBAT remained in anti-tank platoons in Berlin to supplement MILAN until the late 1980s, due to the expected engagement ranges should the Warsaw Pact have ever attacked. The wire guidance of MILAN would also have been problematic in the built up areas of Berlin. It was envisioned that Wombat would be used in 'shoot and scoot' attacks mounted on the back of stripped down Land Rover vehicles.
The Wombat replaced the earlier BAT and MOBAT weapons, themselves developments of the wartime designed "Ordnance, RCL, 3.45 in" recoilless rifle, and was in turn replaced by anti-tank guided missiles. The L6 Wombat itself comprised the L12A3 BAT gun, but mounted on a new lightweight carriage. The vertically sliding breech of the BAT and MoBAT was replaced by a lighter horizontally hinged breech. The Wombat was mounted on a small two wheeled carriage, which was removable in order to be moved over obstacles and then locked to the carriage again. The weapon was normally carried in the rear of a specially adapted Land Rover (Portee). The Wombat could also be mounted on the FV432/40 armoured personnel carrier.
The usual round for Wombat was a HESH, which it could fire out to around 1,800 m. The HESH round could defeat 400 mm (16 in) of armour. Other ammunition types include the canister and modified canister rounds. The latter released flechettes, or small darts, giving a "shotgun" effect. These rounds could be used against infantry in the open. The base of the BAT cartridge case was frangible, the reaction gases venting directly backwards through a single large venturi. This was in contrast to the US recoilless designs, which used a frangible sidewall to the cartridge case and multiple venturi.
During the Cold War era, NATO and British Royal Marine forces used the Swedish made Snow Trac as a carrier for the L6 Wombat in the snow-covered mountains of Norway.8.8 cm Raketenwerfer 43
The 8.8 cm Raketenwerfer 43 Puppchen was an 88 mm calibre reusable anti-tank rocket launcher developed by Nazi Germany during World War II.
Raketenwerfer 43 was given to infantry to bolster their anti-tank capability. The weapon was fired from a small two-wheeled gun carriage which fired a percussion-primed, rocket-propelled, fin-stabilized grenade RPzB. Gr. 4312 with a shaped charge warhead. The grenade had a shorter tailboom of 490 mm (19 in) compared to the 650 mm (26 in) tailboom for the electrically-primed grenade RPzB. Gr. 4322 for the Panzerschreck. Both grenades used identical warhead and fuzing.Approximately 3,000 units were completed from 1943 to 1945. It was made in much smaller numbers than either the Panzerschreck, which was based on the American Bazooka rocket launcher, or the Panzerfaust, which was a disposable anti tank recoilless rifle. This is partly because it was realized that a simple hollow tube with an ignition device was all that was needed to launch the 88 mm rocket, rather than an elaborate miniature artillery piece with carriage and breech. Due to the carriage and better sights, the accuracy was better, and the range more than double that of the Panzerschreck. However, Raketenwerfer 43 was more expensive, heavier and had longer production time than Panzerschreck or Panzerfaust.B-10 recoilless rifle
The B-10 recoilless rifle (Bezotkatnojie orudie-10, known as the RG82 in East Germany) is a Soviet 82 mm smoothbore recoilless gun. It could be carried on the rear of a BTR-50 armoured personnel carrier. It was a development of the earlier SPG-82, and entered Soviet service during 1954. It was phased out of service in the Soviet Army in the 1960s and replaced by the SPG-9, remaining in service with parachute units at least until the 1980s. Although now obsolete it was used by a large number of countries during the Cold War.B-11 recoilless rifle
The B-11 recoilless rifle (It is also known as RG107) is a Soviet 107 mm smoothbore recoilless gun. It entered service in 1954, and was typically towed by a 6x6 ZIL-157 truck or a UAZ 4x4 truck.Designed by KB Mashinostroyeniya (KBM), Kolomna.
It is fitted using a PBO-4 sight which has a 5.5x zoom direct fire sight and a 2.5x zoom sight for indirect fire.Carl Gustaf recoilless rifle
The Carl Gustaf recoilless rifle (Swedish pronunciation: [ˈkɑːɭ ²ɡɵsːtav]) is an 84 mm man-portable reusable anti-tank weapon produced by Saab Bofors Dynamics (formerly Bofors Anti-Armour AB) in Sweden. Introduced in 1946, it was one of the many recoilless rifle designs of that era. While similar weapons have generally disappeared from service, the Carl Gustaf is still being made and remains in widespread use today. The Carl Gustaf is a lightweight, low cost weapon that uses a wide range of ammunition, which makes it extremely flexible and suitable in a wide variety of roles.
In Sweden, it is officially called the Grg m/48 (Granatgevär – "grenade rifle", model 1948). British troops refer to it as the "Charlie G", while Canadian troops often refer to it as "Carl G". In U.S. military service, it is known as the "M3 Multi-Role Anti-Armor Anti-Personnel Weapon System" (MAAWS) or "Ranger Anti-tank Weapons System" (RAWS), but is often just called the "Gustaf Bazooka", "Gustaf", or "Goose". In Australia, it is irreverently known as "Charlie Gutsache" (guts ache, slang for stomach pain), or "Charlie Swede".Jagdfaust
The Sondergerät SG 500 Jagdfaust ("hunting fist") or Jägerfaust ("hunter's fist") was an experimental airborne anti-bomber recoilless rifle designed for use in the Me 163 Komet rocket plane by the German Luftwaffe during World War II.List of World War II weapons of the United States
Below are lots of different types of weapons used in World War II by the United States.List of weapons of the Cambodian Civil War
The Cambodian Civil War was a conflict between the forces of the Khmer Rouge and the royal forces of the Kingdom of Cambodia from 1967 to 1970, then between the National United Front of Kampuchea and the Khmer Republic from 1970 to 1975.M18 recoilless rifle
The M18 recoilless rifle is a 57 mm shoulder-fired, anti-tank recoilless rifle that was used by the U.S. Army in World War II and the Korean War. Recoilless rifles are capable of firing artillery-type shells at reduced velocities comparable to those of standard cannon, but with greater accuracy than anti-tank weapons that used unguided rockets, and almost entirely without recoil. The M18 was a breech-loaded, single-shot, man-portable, crew-served weapon. It could be used in both anti-tank and anti-personnel roles. The weapon could be both shoulder fired or fired from a prone position. The T3 front grip doubled as an adjustable monopod and the two-piece padded T3 shoulder cradle could swing down and to the rear as a bipod for the gunner. The most stable firing position was from the tripod developed for the water-cooled Browning M1917 machine gun.M20 recoilless rifle
The M20 recoilless rifle is a U.S. 75 mm caliber recoilless rifle T21E12 that was used during the last months of the Second World War and the M20 extensively during the Korean War. It could be fired from an M1917A1 .30 caliber machine gun tripod, or from a vehicle mount, typically a Jeep. Its shaped charge warhead, also known as HEAT, was capable of penetrating 100 mm of armor. Although the weapon proved ineffective against the T-34 tank during the Korean War and most other tanks, it was used primarily as a close infantry support weapon to engage all types of targets including infantry and lightly armored vehicles. The M20 proved useful against pillboxes and other types of field fortifications. Its poor armor penetration by the HEAT round was because of it being a spin-stabilized projectile rather than the later fin-stabilized rounds used in the 106mm M40 recoilless rifle.M40 recoilless rifle
The M40 recoilless rifle is a lightweight, portable, crew-served 105 mm recoilless rifle made in the United States. Intended primarily as an anti-tank weapon, it could also be employed in an antipersonnel role with the use of an antipersonnel-tracer flechette round. The bore was commonly described as being 106 mm caliber but is in fact 105 mm; the 106 mm designation was intended to prevent confusion with incompatible 105 mm ammunition from the failed M27. The air-cooled, breech-loaded, single-shot rifle fired fixed ammunition and was used primarily from a wheeled ground mount. It was designed for direct firing only, and sighting equipment for this purpose was furnished with each weapon, including an affixed spotting rifle.
Replacing the M27 recoilless rifle, the M40 primarily saw action during the Vietnam War and was widely used during various conflicts thereafter in Africa or in the Middle East. It was replaced by the BGM-71 TOW anti-tank missile system in the US armed forces.M67 recoilless rifle
The M67 recoilless rifle was a 90 mm (3.55 inch) anti-tank recoilless rifle made in the United States and later in South Korea. It could also be employed in an anti-personnel role with the use of the M590 antipersonnel round. It was designed to be fired primarily from the ground using the bipod and monopod, but could also be fired from the shoulder using the folded bipod as a shoulder rest and the monopod as a front grip. The weapon was air-cooled and breech-loaded, and fired fixed ammunition. It is a direct fire weapon employing stadia lines to allow simple range finding, based on a typical tank target bridging the lines once in range.MK 115 cannon
The MK 115 (German: Maschinenkanone 115—"machine cannon 115") was an autocannon developed in Germany in late World War II by Rheinmetall-Borsig for use in aircraft. It was an unusual development in that although it employed a locked breech, it also used a funnel to allow some of the propellant gases to escape out the rear in order to reduce recoil when firing, essentially being an automatic recoilless rifle. The MK 115 was chambered for a 5.5 cm round (in common with a few other late-war German designs), but used a partially combustible cartridge, leaving only the base of the cartridge to eject. The MK 115 was a gas-operated, belt-fed weapon, and its breechblock used a swinging lock mechanism. It had a rifled barrel with an 8°30′ twist. A single prototype in the late stages of development was captured by the Western allies.Operation Karbala-6
Operation Karbala-6 was an Iranian operation during the Iran–Iraq War to prevent Iraq from rapidly transferring units to its defense lines at Basra after Iran had launched Operation Karbala-5 to capture the city of Basra.
Iran used Basij militiamen armed with Kalashnikovs and RPG-7s, the Army's 77th Mechanized Division of Khorasan equipped with M47 and M48 tanks, 106mm recoilless rifle, 130mm and 230mm artillery, supported by attack helicopters, and Pasdaran's 31st Ashura Division which was armed with captured Iraqi tanks.Orfey-class destroyer
The Orfey-class destroyers were built for the Baltic Fleet of the Imperial Russian Navy. They were modified versions of the earlier destroyer Novik and the Derzky class. These ships were larger, had triple torpedo tubes and an extra 102 mm (4.0 in) gun. One ship, Engels, was fitted with a 305 mm (12 in) recoilless rifle for testing in 1934. Fourteen ships were completed in 1914–1917 and fought in World War I and during the Allied intervention in the Russian Civil War. The survivors fought in World War II.PF-98
The Type 98 (PF-98) is a 120mm unguided anti-tank rocket system developed by Norinco for the People's Liberation Army as a successor to the Type 65 and Type 78 recoilless guns. It is also known by its nickname, "Queen Bee".Paraguayan Army
The Paraguayan Army is an institution of the State of Paraguay, organized into three divisions and 9, and several commands and directions, went to war three occasions, in the War of the Triple Alliance (1864–1870) against Brazil, Argentina and Uruguay, Chaco War (1932–1935) against Bolivia, and the ongoing Paraguayan People's Army insurgency.SPG-9
The SPG-9 Kopye (Spear) is a tripod-mounted man-portable, 73 millimetre calibre recoilless gun developed by the Soviet Union. It fires fin-stabilised, rocket-assisted HE and HEAT projectiles similar to those fired by the 73 mm 2A28 Grom low pressure gun of the BMP-1 armored vehicle. It was accepted into service in 1962, replacing the B-10 recoilless rifle.Vespa 150 TAP
The Vespa 150 TAP was an anti-tank scooter made in the 1950s from a Vespa scooter for use with French paratroops (troupes aéroportées, TAP). Introduced in 1956 and updated in 1959, the scooter was produced by Ateliers de Construction de Motocycles et Automobiles (ACMA), the licensed assembler of Vespas in France at the time. Modifications from the civilian Vespa included a reinforced frame and a three-inch recoilless rifle mounted to the scooter.
The 150 TAPs mounted a M20 75 mm recoilless rifle, a U.S.-made light anti-armour cannon. It was very light in comparison to a standard 75 mm cannon but was still able to penetrate 100 mm of armour with its HEAT warhead. The recoil was counteracted by venting propellant gases out the rear of the weapon which eliminated the need for a mechanical recoil system or heavy mounts, enabling the weapon to be fired from the Vespa frame.
The scooters would be parachute-dropped in pairs, accompanied by a two-man team. The gun was carried on one scooter, while the ammunition was loaded on the other. Due to the lack of any kind of aiming devices the recoilless rifle was never designed to be fired from the scooter; the gun was mounted on a M1917 Browning machine gun tripod, which was also carried by the scooter, before being fired. However, in an emergency it could be fired while in the frame, and while the scooter was moving.
The "Bazooka Vespa" was relatively cheap: Vespas cost roughly US$500 at the time, and the M20s were plentiful. 600 of them were produced, between 1956 and 1959. It had a cart, and also came with two cans of fuel
The scooter themselves were original civilain produced VB1T models, 150 cc capacity engine. The engine was two stroke, top speed of 60kph, enough speed to ram any vehicles if needed in an emergency, or move the user from the drop site to the area where the paratrooper was needed.