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72-621: One major disadvantage of the MG FF cannon was its extremely low ammunition count. One cannon only carried 90 bullets, and these were fired very quickly. MG FF stands for Maschinengewehr Flügel Fest , which translates into "machine gun, wing, fixed"; this reflects the fact that in Luftwaffe practice guns of 20 mm or less were designated as "machine guns" ( maschinengewehr ) as opposed to larger "machine cannons", or autocannons, which were "MK", for maschinenkanone . The "wing, fixed" part reflects

144-734: A built-in cocking system and could simply be re-cocked in flight after a misfire, which made the misfires less of a problem than with other aircraft. The U.S. followed the British development closely and when the Mk.V was designed, the Americans followed suit with the A/N M3 but unreliability continued. After the war the United States Air Force (USAF) adopted a version of the M3 cannon as

216-596: A concept that was quickly taken up by other companies. Notable among the resulting designs was the Swiss Oerlikon FF S , which was based on the Becker but introduced a number of improvements. In the 1930s, Hispano-Suiza was asked to develop a 20 mm cannon to fire through the propeller shaft (as a moteur-canon SS) of a gear-reduction inline aviation engine like the Hispano-Suiza 8BeC . They took out

288-581: A contained explosion" to "shells damaging through the shock wave created from the explosion of their payload, rather than the combination of fragmentation and pressure wave damage like traditional high-explosive shells , which have thicker shell walls and smaller explosive load". The name 'mine shell' in English is a modern term directly translated from the German military term Minengeschoß ("mine shot"). The historical equivalent English military term

360-540: A cylinder, the Minengeschoß design when applied to larger calibers allowed a dramatic increase in explosive payload and power. One such weapon was the 30 mm (1.18 in) MK 108 which became highly militarily significant during the second half of the war, when the Allies began to mount their enormous bombing onslaught on German cities. So large was the increase in internal volume indeed that it proved worthwhile to

432-635: A fixed mount 160 ) rounds. Since in most installations the latter was more popular, the small ammunition capacity was a weakness. In 1940, Hispano-Suiza was developing a belt-feeding system, as well as derivatives of the HS.404 in heavier calibres such as 23 mm but these projects were halted with the German occupation of France. Before the Second World War, the United Kingdom had embarked on

504-419: A heavier projectile with more inertia. It is also a consideration that the lower recoil makes them unsuitable to be fired from the same gun as standard shells of comparable power, if it uses a recoil operated or advanced primer ignition mechanism. Mine shells are thus often longer in construction compared to other projectile types of the same caliber to increase the weight with more mass in an attempt to reduce

576-556: A heavy bomber in a single hit. Due to requirements for minimalism, it was calculated that a caliber of at least 55 mm (2.17 in) was needed to deliver this load. Interestingly Germany already manufactured mine shells in caliber 50 mm (1.97 in) for guns like the 5 cm FlaK 41 , but these only had an explosive charge capacity of 360 grams (0.794 pounds). In the end, no 55 mm mine shells seems to have been deployed by Germany during World War II. The allied bombing of Germany delayed weapons-research and made production of

648-696: A license on the Oerlikon FF S and made minor modifications to produce the Hispano-Suiza Automatic Cannon Type HS.7 and HS.9. Shortly after production began, the Hispano-Suiza and Oerlikon companies disagreed over patent rights and their business connection came to an end. In 1933, the chief engineer of Hispano-Suiza, Marc Birkigt , began work on the design of a new weapon to replace the Oerlikon contract, based on

720-585: A lighter round for better muzzle velocity in the Colt Mk 12 cannon . As a ground vehicle-mounted gun, either anti-aircraft or as a general-purpose autocannon, the HS.404 lasted into the 1960s. A powered turret variant is still in production in Honduras and is used as a light anti-aircraft gun by the army and navy in several nations. The AN/M3 was developed into the Mk12 Colt 20 mm automatic cannon, one of

792-541: A locking mechanism patented in 1919 by the Swedish-American machine-gun designer Gustaf Swebilius  [ sv ] . The result was the Type 404 or HS.404. While the HS.404 resembled the parent Oerlikon FF S in many respects, its repeating mechanism was a gas-operated locking bolt. On firing the 404, when the projectile passes a hole cut in the barrel, about halfway along its length, high-pressure gas behind

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864-580: A mixture called HA 41 ( RDX + Aluminium powder)(the latter had a 40 percent increased high explosive and incendiary effect). The MG FF and FF/M saw widespread use in fighters such as the Bf 109 E-3 to F-1, Bf 110 C to F, and Fw 190 A-1 to A-5. Early variants of the Fw 190 (A-1 to A-5) were typically fitted with an inboard pair of MG 151 and an outboard pair of MG FF/M, although the MG FF/M were sometimes removed in

936-400: A muzzle velocity of c. 700 m/s and a rate of fire of c. 540 rounds per minute. AP, HE and incendiary projectiles were also available (115 to 117 g projectiles, 585 m/s, c. 520 rpm) because the mine-shot was not capable of holding incendiary or tracer parts. There were also different types of high-explosive mine shell fillings with either standard Pentrit A ( PETN + Aluminium ),

1008-652: A programme to develop cannon-armed fighters. They acquired a licence to build the HS.404, which entered production as the Hispano Mk.I intended as aeroplane armament. Its first use was in the Westland Whirlwind of 1940 and later in the more powerful Bristol Beaufighter , providing the Royal Air Force (RAF) with powerful cannon-armed interceptors. The experience of the Battle of Britain had shown

1080-463: A total full round length of 184 mm (7.244 in) regardless of projectile type. The gun had a muzzle velocity between 840 and 880 m/s (2,800 and 2,900 ft/s), depending on barrel length. Rate of fire was between 600 and 850 rounds per minute. The gun was 2.36 m (7 ft 9 in) long, weighing between 42 and 50 kg (93 and 110 lb). The British Mk V and American M3/M24 weapons were lighter and had higher rates of fire than

1152-459: Is High-Explosive, High-Capacity , abbreviated as HEHC , which has become uncommon or obsolete in modern times. The name mine shell is or has however been present in several different military nomenclatures around the world besides Germany and the United Kingdom; although in modern times only a few countries still use the term "mine shell" (or equivalent) and its umbrella terms in military nomenclature. Examples of military nomenclatures around

1224-436: Is a military explosive shell type characterized by thin (usually steel) shell walls and a correspondingly high quantity of explosives , much higher than the traditional high-explosive shell type per caliber , meaning that mine shells trade fragmentation effect (due to the thinner shell walls) for a higher pressure wave effect when comparing to traditional high-explosive shells. Mine shells were originally developed during

1296-660: Is achieved at a distance of 20–150 cm after projectile fragmentation. Hispano-Suiza HS.404 The HS.404 is an autocannon originally designed by and produced by the Swiss arm of the Spanish/Swiss company Hispano-Suiza in the mid-1930s. Production was later moved to the French arm of Hispano-Suiza. It was widely used as an aircraft, naval and land-based weapon by French, British, American and other military services, particularly during World War II . The cannon

1368-417: Is also referred to as Birkigt type 404 , after its designer Marc Birkigt and later versions based on British development are known as 20 mm Hispano . Firing a 20 mm calibre projectile, it delivered a significant load of explosive from a relatively light weapon. This made it an ideal anti-aircraft weapon for mounting on light vehicles, as well as a fighter aircraft gun, supplementing or replacing

1440-460: Is unknown but Italy was using the name by 1884 ( Italian : Granata Mina ). Mine shells were used in a lot of different types of high caliber cannons , howitzers , and mortars on both land and on water around the turn of the century, before seeing a decline after World War I . (See the article Minenwerfer for the use of mine shells in mortars during World War I .) The use of rebar -reinforced fortifications during World War I probably made

1512-571: The 7.62 mm (.30 calibre) and .303 inch (7.7 mm) machine guns commonly used in military aircraft of the 1930s. The HS.404 was produced by the French subsidiary of Hispano-Suiza, and under license by a variety of companies in other countries. The first widely used 20 mm aircraft cannon was the Becker model , introduced into German service in World War I . The Becker introduced the advanced primer ignition blowback (API) design for autocannons,

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1584-534: The Hawker Hurricane and Supermarine Spitfire had shown a tendency for the gun to jam during combat manoeuvres, leading to some official doubt as to the suitability of cannon as the sole main armament. This led to the Air Ministry for a brief period specifying 12-machine gun armament for new fighters. A suitable belt-feeding system was developed by Martin-Baker and the new design was adopted by

1656-567: The M -Shell, it was intended to replace the HEI grenade. When the projectile broke up, the phosphorus remained in effective parts in the target and burned for a long time. The prerequisite for disintegration of the projectile were sufficiently resistant targets, namely armour plates of at least 3 mm at 45°, at least 4.5 mm at 60°, at least 7 mm at 75°, at least 15 mm at 90°, impact angle; also aircraft components (strong spars and struts). The incendiary effect against protected containers

1728-611: The M24 , similar in most respects except for the use of the addition of electrical cocking, allowing the gun to re-cock over a lightly struck round. The problems of the American weapons led to most U.S. fighters being equipped with the AN/M2 .50 cal Browning light-barrel machine gun throughout the war. After the war, the Hispano variants disappeared fairly quickly as fighter armament due to

1800-821: The "high-explosive" shells of Britain's ADEN cannon and the French DEFA 540 were effectively clones of German wartime equivalents. The guns themselves were developments of the German Mauser MK 213 . Even in comparison to modern designs, some of the WW2 payloads quoted above are impressive as not even the PGU-13/B HEI round for the GAU-8 /A Avenger gun of the A-10 Warthog or the 30 mm OFZ shell of Russian GSh-30-1 and GSh-30-6 cannons come close to

1872-540: The 55 mm weapons impossible. It should be noted however that the Germans did manage to deploy a 55 mm air-to-air rocket named " Rakete, 4 Kg, Minenkopf " (Rocket, 4 kg, Mine-head), or R4M for short, at the end of 1944. It was fitted with a 55 mm "high-capacity", or "mine" warhead filled with 520 gram of the explosive-mixture "HTA 41" (also known as "HTA 15"), which consists of 40% Hexogen ( RDX ), 45% TNT and 15% aluminium . The shell walls of

1944-650: The Ausf.B was a training shell without explosives.) See below for a comparison with modern ammunition loads. Mine shells where also adopted for use in ground attack cannons like the high-velocity 30 mm MK 103 , among others, as well as anti-aircraft guns like the 2 cm Flak 30/38 , 3.7 cm Flak 18/36/37/43 and 5 cm FlaK 41 . At the end of the WWII the Germans started to develop several autocannons in caliber 55 mm (2.17 in) for use in aircraft and anti-aircraft guns against allied aircraft. Some examples being

2016-535: The German WW2 mine shells of the same caliber - 72–85 g (2.54–3.00 oz) compared to 58 g (2.05 oz) and 48.5 g (1.71 oz) respectively for the PGU-13B and OFZ. Sweden having experience with the shell type from earlier developed several different mine shells in several different calibers after the war. Some examples being a mine shell variant for the 20 x 110 Hispano cartridge and one for

2088-629: The German WW2 rocket R4M was an abbreviation of Rakete, 4 Kg, Minenkopf , meaning "Rocket, 4 kg (8.8 lb), Mine-head" in English. Interestingly, mine-rockets developed in Sweden after WW2 were named sprängraketer (high-explosive rockets), even though their initial design was directly based on the German R4M. Dedicated mine shells originate in Europe . The origin of the name "mine shell"

2160-447: The Germans to refine these projectiles by making them more streamlined, sacrificing a little of this capacity, but thus partly compensating for the lower momentum characteristic of the Minengeschoß design. These streamlined mine shells for the 30 mm MK 108 were designated Ausf.C. and featured 72 grams (2.54 ounces) of nitropenta (PETN), compared to the original blunt-nosed Ausf.A which had 85 grams (3.00 ounces) of PETN. (Note that

2232-513: The Gerät 58 anti-aircraft gun and the MK 112 and MK 115 aircraft cannons . The reason the Germans settled on an unconventional caliber of 55 mm was due to it being the smallest caliber that could shoot down a heavy bomber with a single mine shell. Calculations and tests had revealed that a single explosion of 400 grams (0.882 pounds) of PETN or RDX explosive mixes could effectively take out

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2304-680: The HS.404 made it well suited to mounting on vehicles. The M16, an anti-aircraft version of the M3 Half-track , could be equipped with single or double American made copies of the Hispano-Suiza auto-cannon. This variant of the M3 Half-track was used by US and Commonwealth forces late in the Second World War , in the Korean War and was further developed by Israel in the post-war era. In 1938, an aircraft based version of

2376-443: The HS.404 was produced at the request of the French government. It was installed on a wide range of pre-war French fighter aircraft, notably in installations firing through the propeller shaft of the Hispano-Suiza 12Y engine, a system referred to as a moteur-canon (engine cannon). Due to the closed-bolt design the cannon was also suitable for synchronisation gear. The HS.404 was fed by drum magazines that could accommodate 60 (or in

2448-453: The Hispano to the US but this production never became satisfactory and the British eventually gave up on the US versions. British production was eventually increased to the point where this was no longer necessary. The ultimate version of the British wartime Hispanos was the Hispano Mk. V , which had a shorter barrel , and lacked the cocking cylinder thus requiring manual cocking before flight. It

2520-400: The Luftwaffe found they had created a potential game-changer as the recoil/velocity ratio made it possible to create larger caliber guns that would have low enough recoil to be effectively mounted on conventional aircraft, while at the same time achieving useful velocities. Moreover, as the volume of a cylinder is proportional to the square of its radius, and as cannon shells tend to the shape of

2592-467: The Luftwaffe's mine shells was significant. Considering the high-explosive rounds alone as an example: the 20 mm mine shells used in MG ;FF/M cannons (and later in the MG 151/20) both had a 17 g (0.60 oz) HE filling while British and American autocannon shells of the same calibre, but markedly heavier, could carry only 10–12 g (0.35–0.42 oz), while the typical filler load in

2664-459: The MG FF was often replaced with the 20 mm MG 151/20 from 1941 onwards, it saw a comeback in 1943 as the primary Schräge Musik gun in the Bf 110 (and other) night fighters, as it fit perfectly into the rear cockpit, and muzzle velocity was less important in this application (there were also stocks of surplus guns and ammunition to be used up). As soon as it hit the outer skin of the aircraft,

2736-720: The RAF and Fleet Air Arm in 1941 in a slightly modified form as the Hispano Mk.II . Four cannons replaced the eight Browning machine guns in the Hurricane and in some tropical versions of the Spitfire, becoming standard armament in later fighters. Most other Spitfires had only two cannons because the outboard cannon tended to freeze at high altitudes. These were complemented with four 0.303 calibre (7.7 mm) or two 0.50 calibre (12.7 mm) machine guns. The British were concerned their production would be inadequate and licensed production of

2808-475: The batteries of eight rifle-calibre M1919 Browning machine guns to be inadequate and prompted the adoption of autocannon armament for the primary portion of RAF fighters. The Beaufighter highlighted the need for a belt feed mechanism; as a night fighter the 60-round drums needed to be replaced in the dark by the Radar / Wireless Operator, often while the aircraft was manoeuvring. The early trial installations in

2880-519: The bolt was locked during firing, it could be lighter than that of the Oerlikon, thus facilitating an increase in rate of fire to 700 rounds per minute (rpm), a gain of about 200 rpm. In 1938, Birkigt patented it and started production in their Geneva factory. The HS.404's predecessor, the Oerlikon type S auto-cannon, was rather heavy, and the movement of the heavy bolt made it best suited in static and maritime anti-aircraft defence. The lighter bolt of

2952-430: The cavity for fuse and explosives into a solid steel shot, and neither process was effective at making small projectiles with walls that were sufficiently thin yet strong enough to work as a mine shell. While small thick-walled shells fired from automatic guns performed well against ground targets, they were more limited in anti-aircraft use. In the late 1930s, the Germans began to pay attention to these shortcomings during

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3024-676: The combination of fragmentation and a correspondingly smaller blast achieved by classic high-explosive shells . This is referred to as pressure wave effect/damage in for example Swedish ( Swedish : tryckvågsverkan ). This effect is desirable when attacking non- reinforced materials such as brick , concrete or aircraft skin , as these are relatively brittle and easy to penetrate and therefore do not need to be tackled with heavy, hard projectiles, but are tough enough to maintain their structure despite being pierced by shellfire and fragmentation. The larger explosions generated by mine shells are more efficient at inflicting damage on such targets than

3096-442: The conventional 20 mm shells of the original MG-FF was a mere 4.5–6.5 g (0.16–0.23 oz). As mentioned above, one problem with the new ammunition was that due to their lightweight nature, the new 20 mm mine shells produced insufficient recoil to operate the 20 mm MG FF cannon. This required a modification of the recoil mechanism so the cannon could fire this new shell, but this in turn made it unsafe to fire

3168-621: The early HS.404 guns. Ammunition was shipped in rectangular 10-shell fiberboard cartons. There were 12 cartons per metal-lined wooden packing crate (120 rounds). The M90 series of shells were ballistically matched to make it easier to use different types without losing accuracy. Ammunition was shipped in 25-round metal canisters. There were six metal canisters per wooden crate (150 rounds). Mine shell A mine shell (from German : Minengeschoss , "mine shot") or high-explosive, high-capacity ( HEHC ) in British military nomenclature ,

3240-523: The fact that the primary motivation behind its design was to create a 20 mm caliber weapon that was compact and light enough to be mounted in the wings of aircraft, especially fighters. Compared to rival designs, such as the Hispano-Suiza HS.404 – which had been developed from the larger Oerlikon FF S – the MG FF had some disadvantages, such as low rate of fire and low muzzle velocity , as well as limited ammunition storage in its drums. On

3312-635: The field in order to save weight. The MG FF/M fed from a 60-round drum that required an underwing bulge to fit within the wing (90 rounds in the A-5). From the A-6 onward, the MG FF/M were replaced by a pair of MG 151/20 feeding from 125 round belts, or deleted altogether. The cannon was also fitted to bombers such as the Do 217 , Ju 88 , He 111 , Do 17 , as well as many other aircraft, either as aerial defense, or more often for anti-ship and defensive fire suppression. Although

3384-455: The first proto-landmines developed received the name mine. These were basic explosives dug down into the ground like a mine. This eventually led to mine-ordnance being defined as "contained explosions", which is alluded to in the name mine shell as its original purpose was to penetrate into fortification walls and burst inside. However, as mine shells became obsolete against fortresses the definition changed with time from "shells damaging through

3456-431: The greater kinetic impact but smaller detonations delivered by conventional rounds. To achieve this effect mine shells feature very thin shell walls and thus more room for explosive filler; though at the cost of generating lighter and thus somewhat less formidable shrapnel (fragmentation). Against thicker targets, such as brick or concrete walls, they often also feature a delayed action on the fuze so they can penetrate into

3528-420: The ground by the aircraft armourers before flight, the pneumatic cocking mechanism used previously being regarded as unnecessary weight and detrimental to aircraft performance; any stoppage in flight made the gun unusable until it could be cleared on the ground. The misfires also had the tendency to cause aircraft with wing-mounted guns to yaw away from the wing with the failed gun when the guns were fired, due to

3600-411: The guns had a poor rate of fire, relatively sluggish muzzle velocity and an inadequate magazine ammunition feed, and were soon to be replaced by the belt-fed MG 151 . This new type was originally introduced as a Minengeschoß-firing heavy machine gun, in 15 mm; but then it was realised that the earlier cannon-sized mine shells were more effective, and so a new larger cartridge (20x82mm) was created for

3672-565: The guns remained unsuitable. The U.S. Navy had been trying to switch to using cannon on all its combat aircraft throughout the war but the conversion never occurred. As late as December 1945 the U. S. Army Chief of Ordnance was still attempting to complete additional changes to the design to allow it to enter service. Some variations of the 20 mm guns used on the Lockheed P-38 Lightning aircraft were produced by International Harvester . The P-38's nose-mounted M2 featured

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3744-530: The introduction of revolver cannon , based on the prototype versions of the un-built German wartime Mauser MG 213 design. The British introduced the powerful revolving 30 mm ADEN cannon in most of their post-war aircraft, while the French used the similar DEFA cannon , firing similar ammunition. The USAF introduced the 20 mm M39 cannon to replace the M24, while the Navy combined the original Hispano design with

3816-537: The main weapons on boats of the Mobile Riverine Force in the Vietnam War and also used on some larger amphibious ships. The Hispano fired a 130 grams (4.586 oz) 20 mm diameter projectile from a 110 mm (4.331 in) long casing, the whole round weighing 257 g (9.065 oz). Lengths of the projectiles varied with type but were set to variable depth in the casing to produce

3888-431: The mid- to late 1800s against fortresses prior to rebar but got a new role during World War II against air targets as reinforced fortresses had made the original use of the type obsolete around World War I . The mine shell is a more explosive version of the common high-explosive and high-explosive fragmentation shells, relying on inflicting damage primarily through the blast (pressure wave) alone rather than via

3960-510: The new mine shell, but accidentally using the heavier MG FF ammo could damage the gun. In the interest of avoiding such errors, the weapon was redesignated the MG FF/M. It was introduced with the Bf 109 E-4 and Bf 110 C-4 in summer 1940. The MG FF fired a 134 g projectile with a muzzle velocity of some 600 m/s and a rate of fire of about 530 rounds per minute. The MG FF/M fired a 90 g HE/M (high explosive mine shell) projectile with

4032-404: The old, conventional rounds. In an effort to avoid the chambering of incorrect ammunition, the modified weapon was redesignated the 20 mm MG FF/M, M for Minengeschoß . Germany first used Minengeschoß ammunition during the Battle of Britain when MG FF /M armed Bf 109 E's and Bf 110 C's flew missions over from mainland Europe to Britain. Although the shells themselves proved deadly,

4104-550: The other hand, it was much lighter and shorter. Even with its compact size, wing installation on the Messerschmitt Bf 109 and Focke-Wulf Fw 190 fighters was not easy, as the drum required substantial space, and as a consequence the ammunition storage was initially reduced to 60 shells per drum. An ammunition drum of 90-round nominal capacity was developed for the Fw 190 A-5, and retrofitted to some earlier variants. There were also experiments with belt feedings. The MG FF

4176-430: The primer charge in the fuze head responded, shearing the fuze head away and igniting the incendiary charge in the projectile. The incendiary charge sprayed forward over at least 10 m of projectile travel. In air combat as a carrier of the incendiary effect, especially for the incendiary shooting of fuel tanks. As an indestructible body, it remained effective even after penetrating several bulkheads. In combination with

4248-513: The production of ammunition . When delivered, the guns proved to be extremely unreliable and suffered a considerable number of misfires due to the round being lightly struck by the firing pin . The British were interested in using this weapon to ease the demand on production in England but after receiving the M1 they were disappointed. British wing-mounted fighter weapons by this period were cocked on

4320-412: The projectile is siphoned off and operates a piston that drives a rod, running along the top of the barrel, back against a cam on the bolt, unlocking it and allowing the remaining high pressure gases in the barrel to propel it and the spent cartridge backwards in a delayed sequence that allows the bolt to remain closed until the projectile has exited from the barrel. This maximizes muzzle velocity and since

4392-497: The shell obsolete as its effect on fortifications was negated by the rebar . During World War II , mine shells would see a resurgence as the Germans started to use the type in small caliber (initially 20 mm) automatic weapons , both to arm the Luftwaffe's fighter aircraft and for Flak . This was an innovation, as prior to this, mine shells had only been constructed in large calibers for technical reasons. Larger shells were usually produced by casting, smaller calibers by drilling

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4464-585: The trials of the 20 mm MG FF cannon . Its conventional high-explosive rounds were judged unsatisfactory in the anti-aircraft role, for the reasons mentioned above. As a result of these trials, the German air ministry, the Reichsluftfahrtministerium , or RLM for short, ordered the development of mine shells for the 20 mm MG FF cannon in 1937. To make such shells in 20 mm (0.787 in) caliber, German ordnance engineers had to try new methods of construction; what they came up with

4536-565: The unequal recoil , throwing off the pilot's aim. In April 1942 a copy of the British Mk.II was sent to the U.S. for comparison. The British version used a slightly shorter chamber and did not have the same problems as the U.S. version of the cannon. The U.S. declined to modify the chamber of their version but nonetheless made other modifications to create the unreliable M2. By late 1942 the USAAF had 40 million rounds of ammunition stored but

4608-518: The wall and burst inside it, forcing larger pieces of the targets to break loose. An additional advantage of the mine shell approach is that, with explosives being lighter than metal, the projectiles weigh correspondingly less, which gives them higher muzzle velocity compared to heavier shells. For the same reason, they also generate less recoil. However less desirably, the reduced mass inevitably entails that they will possess less momentum, which reduces their range as velocity falls off more rapidly than in

4680-644: The warhead were only 0.8 mm (0.0315 in) thick. These rockets were fitted to several German aircraft at the end of the war, most notably the Me 262 , which used them to great effect during their limited service life. On one occasion, Me 262s armed with R4M rockets shot down 25 B-17 bombers out of a group of 425 within a very short time without any losses. After the defeat of Germany in World War II, several countries started using mine shells for their own post-war aircraft and anti-aircraft armament, for example

4752-458: The weapon. The adapted gun, (more precisely designated the MG 151/20), became the Luftwaffe's standard 20 mm autocannon until the end of the war, and with its high fire rate coupled with good ballistics and high-explosives payload for its caliber was overall among the best aircraft armament of the conflict. As the possibilities of this new application for mine shells became better understood,

4824-478: The weight difference, but also to further increase the damage-output. The word 'mine' in the name "mine shell" can in the modern world seem confusing, as military use of the word is mainly associated with land mines and naval mines . However the word "mine" is very old and originally had the same meaning as " mining mines". As mines were used during siege warfare in past eras to collapse fortifications , and later blowing up fortifications (see tunnel warfare ),

4896-482: The world using the term mine shell or equivalent: The damage effect of mine shells, often described as "pressure wave damage" or simply named "mine damage/mine effect", has historically been applied to other types of ordnance than cannon shells, most notably aerial bombs (example names: German: Minenbombe , English: High-Capacity bomb ). Air-to-air rockets configured with mine-shell equivalent warheads have also at times featured "mine" in their name. For example,

4968-422: Was a round made from high quality drawing steel , manufactured in the same way in which cartridge cases are made. These new 20 mm mine shells were first used against the RAF in 1940, and proved highly successful. Even when the British and later, to a limited extent the Americans equipped their fighters with autocannon, they always used conventional ammunition. The difference in payloads between these rounds and

5040-424: Was adapted to fire a new type of high-capacity, high-explosive " mine shell " that featured a projectile with thinner walls that allowed increased explosive charge. This projectile was lighter and thus had a higher muzzle velocity than the previous ammunition; this also entailed that it generated less recoil than earlier projectiles requiring a modification of the recoil mechanism. With this modification it could fire

5112-612: Was also licensed for use in the United States as the M1 , with the United States Army Air Corps (USAAC) and U.S. Navy , which concluded that a single HS404 is analogous to three .50 machine guns in firepower while weighing less than twice as much, planning to switch to the 20 mm calibre as soon as the gun could be produced in sufficient numbers. In 1941 a very large building program was established, along with

5184-786: Was lighter and had a higher rate of fire (desirable in aircraft armament), although at the expense of some muzzle velocity. The shorter barrel meant that the weapon could be housed within the wing of a fighter plane, reducing drag and making the gun less vulnerable to freezing and mechanical stress. One of the main British fighters to use the Mk. V was the Hawker Tempest Mk. V Series II, which mounted two cannons in each wing. Ammunition types available included semi-armour piercing, incendiary (SAPI) and high explosive, incendiary (HEI). Around 42,500 Hispano cannons of various marks were manufactured by Birmingham Small Arms (BSA). The British version

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