MG 151 cannon
Encyclopedia
The MG 151 was a 15 mm autocannon
produced by Waffenfabrik Mauser starting in 1940. It was in 1941 developed into the 20 mm MG 151/20 cannon which was widely used on many types of German
Luftwaffe
fighters, fighter bombers, night fighters, ground attack and even bombers as part of or as their main armament during World War II
. The 20 mm MG 151/20 was also fitted on the Italian
World War II
fighter aircraft
of the "Serie 5", the most effective Italian fighters of WWII.
early F-2, and was soon replaced by the 20 mm version to become the standard cannon for the Bf 109F-4 series onwards until it was superseded by the 30 mm MK 108 cannon
.
To create the MG 151/20 round, Mauser simply necked out the MG 151/15's case (i.e. enlarged the opening of the case where the shell fits in) to fit a 20 mm shell—which, incidentally, was the same shell used in the MG FF cannon
—and shortened the length of the case so that the total length of the complete round was the same for both calibres. These measures simplified conversion of the cannon between calibres, so that it was possible to convert the 15 mm to the 20 mm MG 151/20 simply by changing the barrel and making other small modifications. However, this simple modification-based approach was not without its drawbacks. The relatively short case of the 20 mm round, coupled with the larger and heavier 20 mm projectile cost some muzzle velocity
(950 m/s for the 15 mm round vs. 800 m/s for the 20 mm round—a 16% drop). However, in comparison to the earlier MG FF cannon
, the MG 151 had a higher muzzle velocity which gave it a more predictable trajectory and higher impact velocity/longer range.
Nevertheless, the extra HE capacity was considered well worth the loss in muzzle velocity. The basic 20 mm HE round, for example, had almost 30% more explosive content by weight than the 15 mm shell. Furthermore, the MG 151/20 also used the Minengeschoß
("mine shell"), which was made using drawn steel (similar to making cartridge cases) instead of being cast, as was typically done to make cannon shells at the time. The result was a shell with very thin yet strong walls, and hence a very large explosive (or incendiary
) capacity. Indeed, the 20 mm M-shell carried 6-8 times the amount of explosives contained in the 15 mm shell.
The new 20 mm shell was relatively effective against enemy aircraft, with the possible exception of heavily built bombers such as the B-17 Flying Fortress or Avro Lancaster
. German statistics data showed that on average the 151/20 required an average of 25 hits to down a B-17, while 18-20 hits were required to down other 4-engine bomber types, and only four hits were required to down a single-engine fighter. While the larger round rapidly replaced its predecessor—the MG 151/15 was phased out in 1942—German engineers continued research into an even heavier cannon that could rapidly demolish heavy enemy bombers.
Eight hundred MG 151/20 were exported to Japan by a submarine in August 1943 and were used to equip 388 Japanese Ki-61-I Hei
fighters.
The 20 mm MG 151/20 was also fitted on the Macchi C.205
, the Fiat G.55
and Reggiane Re 2005, the most powerful Regia Aeronautica
fighter aircraft
, built around the Daimler-Benz DB 605
engine.
and French Army aviation arm
(ALAT) utilized MG 151/20 cannon as both fixed and flexible armament in various aircraft, including helicopters. The FAF and ALAT jointly developed a rubber-insulated flexible mount for the MG 151/20 for use as a door gun, which was later used in combat in Algeria aboard several FAF/ALAT H-21C assault transport helicopters and on HSS-1 Pirate gunship helicopters. French Matra MG 151 20mm cannons were used by Portugal, Rhodesia and South Africa fitted to their Alouette III helicopters.
The 15mm caliber is similar to a 14.5mm round, developed in World War 2 for the Soviet PTRD
and PTRS
antitank rifles and used in post-war heavy machine guns. Recent developments of 14.5mm High Explosive Incendiary rounds may be regarded as a revival of the 15mm cannon concept.
, a mixture called HA41 (RDX
and aluminium
), and a compressed version where more explosives were compressed into same space using large pressures (XM).
Autocannon
An autocannon or automatic cannon is a rapid-fire projectile weapon firing a shell as opposed to the bullet fired by a machine gun. Autocannons often have a larger caliber than a machine gun . Usually, autocannons are smaller than a field gun or other artillery, and are mechanically loaded for a...
produced by Waffenfabrik Mauser starting in 1940. It was in 1941 developed into the 20 mm MG 151/20 cannon which was widely used on many types of German
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
Luftwaffe
Luftwaffe
Luftwaffe is a generic German term for an air force. It is also the official name for two of the four historic German air forces, the Wehrmacht air arm founded in 1935 and disbanded in 1946; and the current Bundeswehr air arm founded in 1956....
fighters, fighter bombers, night fighters, ground attack and even bombers as part of or as their main armament during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. The 20 mm MG 151/20 was also fitted on the Italian
Italy
Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...
World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
fighter aircraft
Fighter aircraft
A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets...
of the "Serie 5", the most effective Italian fighters of WWII.
History (MG 151/20)
The 15 mm MG 151 was found to have lackluster performance as the main gun on Messerschmitt Bf 109Messerschmitt Bf 109
The Messerschmitt Bf 109, often called Me 109, was a German World War II fighter aircraft designed by Willy Messerschmitt and Robert Lusser during the early to mid 1930s...
early F-2, and was soon replaced by the 20 mm version to become the standard cannon for the Bf 109F-4 series onwards until it was superseded by the 30 mm MK 108 cannon
MK 108 cannon
The MK 108 was a 30 mm caliber autocannon manufactured in Germany during World War II by Rheinmetall-Borsig for use in aircraft.-Development:...
.
To create the MG 151/20 round, Mauser simply necked out the MG 151/15's case (i.e. enlarged the opening of the case where the shell fits in) to fit a 20 mm shell—which, incidentally, was the same shell used in the MG FF cannon
MG FF cannon
The MG FF was a drum-fed, 20 mm aircraft autocannon, developed in 1936 by Ikaria Werke Berlin of Germany. It was a derivative of the Swiss Oerlikon FF F cannon, itself a development of the German World War I Becker 20 mm cannon, and was designed to be used in fixed or flexible mountings, as...
—and shortened the length of the case so that the total length of the complete round was the same for both calibres. These measures simplified conversion of the cannon between calibres, so that it was possible to convert the 15 mm to the 20 mm MG 151/20 simply by changing the barrel and making other small modifications. However, this simple modification-based approach was not without its drawbacks. The relatively short case of the 20 mm round, coupled with the larger and heavier 20 mm projectile cost some muzzle velocity
Muzzle velocity
Muzzle velocity is the speed a projectile has at the moment it leaves the muzzle of the gun. Muzzle velocities range from approximately to in black powder muskets , to more than in modern rifles with high-performance cartridges such as the .220 Swift and .204 Ruger, all the way to for tank guns...
(950 m/s for the 15 mm round vs. 800 m/s for the 20 mm round—a 16% drop). However, in comparison to the earlier MG FF cannon
MG FF cannon
The MG FF was a drum-fed, 20 mm aircraft autocannon, developed in 1936 by Ikaria Werke Berlin of Germany. It was a derivative of the Swiss Oerlikon FF F cannon, itself a development of the German World War I Becker 20 mm cannon, and was designed to be used in fixed or flexible mountings, as...
, the MG 151 had a higher muzzle velocity which gave it a more predictable trajectory and higher impact velocity/longer range.
Nevertheless, the extra HE capacity was considered well worth the loss in muzzle velocity. The basic 20 mm HE round, for example, had almost 30% more explosive content by weight than the 15 mm shell. Furthermore, the MG 151/20 also used the Minengeschoß
Minengeschoß
The Minengeschoß was a high-capacity autocannon ammunition originally developed in Germany and used in the Luftwaffe's larger caliber aircraft armament during World War II. This new type of high-explosive shell differed from conventional H.E. ammunition in that it had much thinner walls...
("mine shell"), which was made using drawn steel (similar to making cartridge cases) instead of being cast, as was typically done to make cannon shells at the time. The result was a shell with very thin yet strong walls, and hence a very large explosive (or incendiary
Incendiary ammunition
-World War I:One of the first uses of incendiary ammunition occurred in World War I. At the time, phosphorus—the primary ingredient in the incendiary charge—ignited upon firing, leaving a trail of blue smoke. They were also known as 'smoke tracer' for this reason. The effective range of...
) capacity. Indeed, the 20 mm M-shell carried 6-8 times the amount of explosives contained in the 15 mm shell.
The new 20 mm shell was relatively effective against enemy aircraft, with the possible exception of heavily built bombers such as the B-17 Flying Fortress or Avro Lancaster
Avro Lancaster
The Avro Lancaster is a British four-engined Second World War heavy bomber made initially by Avro for the Royal Air Force . It first saw active service in 1942, and together with the Handley Page Halifax it was one of the main heavy bombers of the RAF, the RCAF, and squadrons from other...
. German statistics data showed that on average the 151/20 required an average of 25 hits to down a B-17, while 18-20 hits were required to down other 4-engine bomber types, and only four hits were required to down a single-engine fighter. While the larger round rapidly replaced its predecessor—the MG 151/15 was phased out in 1942—German engineers continued research into an even heavier cannon that could rapidly demolish heavy enemy bombers.
Eight hundred MG 151/20 were exported to Japan by a submarine in August 1943 and were used to equip 388 Japanese Ki-61-I Hei
Kawasaki Ki-61
The Kawasaki Ki-61 Hien was a Japanese World War II fighter aircraft used by the Imperial Japanese Army Air Force...
fighters.
The 20 mm MG 151/20 was also fitted on the Macchi C.205
Macchi C.205
The Macchi C.205 Veltro was an Italian World War II fighter aircraft built by the Aeronautica Macchi. Along with the Reggiane Re.2005 and Fiat G.55, the Macchi C.205 was one of the three "Serie 5" Italian fighters built around the powerful Daimler-Benz DB 605 engine...
, the Fiat G.55
Fiat G.55
The Fiat G.55 Centauro was a single-engine single-seat World War II fighter aircraft used by the Regia Aeronautica and the A.N.R. in 1943-1945. It was designed and built in Turin by Fiat. The Fiat G.55 was probably the best type produced in Italy during World War II, but it did not enter...
and Reggiane Re 2005, the most powerful Regia Aeronautica
Regia Aeronautica
The Italian Royal Air Force was the name of the air force of the Kingdom of Italy. It was established as a service independent of the Royal Italian Army from 1923 until 1946...
fighter aircraft
Fighter aircraft
A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets...
, built around the Daimler-Benz DB 605
Daimler-Benz DB 605
|-See also:-Bibliography:* Gunston, Bill. World Encyclopedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9* Jane's Fighting Aircraft of World War II. London. Studio Editions Ltd, 1989. ISBN 0-517-67964-7...
engine.
Postwar Use
After WWII, numbers of ex-Luftwaffe MG 151/20 cannon were removed from inventory and from scrapped aircraft and used by various nations in their own aircraft. The French Air ForceFrench Air Force
The French Air Force , literally Army of the Air) is the air force of the French Armed Forces. It was formed in 1909 as the Service Aéronautique, a service arm of the French Army, then was made an independent military arm in 1933...
and French Army aviation arm
French Army Light Aviation
The French Army Light Aviation is the aviation service of the French Army.-History:The French Army Light Aviation was established on 22 November 1954 for observation, reconnaissance, assault and supply duties.-Composition:...
(ALAT) utilized MG 151/20 cannon as both fixed and flexible armament in various aircraft, including helicopters. The FAF and ALAT jointly developed a rubber-insulated flexible mount for the MG 151/20 for use as a door gun, which was later used in combat in Algeria aboard several FAF/ALAT H-21C assault transport helicopters and on HSS-1 Pirate gunship helicopters. French Matra MG 151 20mm cannons were used by Portugal, Rhodesia and South Africa fitted to their Alouette III helicopters.
The 15mm caliber is similar to a 14.5mm round, developed in World War 2 for the Soviet PTRD
PTRD
The PTRD-41 was an anti-tank rifle produced and used from early 1941 by the Soviet Red Army during World War II. It was a single-shot weapon which fired a 14.5x114mm round...
and PTRS
PTRS-41
The PTRS-41 is the semi-automatic cousin of the PTRD anti-tank rifle.-Design:The PTRS-41 was produced and used by the Soviet Union during World War II. In the years between the World Wars, Soviet Union began experimenting with different types of armour-piercing anti-tank cartridges...
antitank rifles and used in post-war heavy machine guns. Recent developments of 14.5mm High Explosive Incendiary rounds may be regarded as a revival of the 15mm cannon concept.
MG 151 specifications
- Type: single-barrel automatic cannon
- Caliber: 15 mm x 96
- Operation: Recoil-operatedRecoil operationRecoil operation is an operating mechanism used in locked-breech, autoloading firearms. As the name implies, these actions use the force of recoil to provide energy to cycle the action...
; short recoil - Length: 1916 mm
- Barrel length: 1254 mm
- Rifling: 8 grooves, right hand twist, 1 turn in 16"
- Weight (complete): 38.1 kg (84 lb)
- Rate of fire: 740 rpm
- Effective range: 400 m
- Muzzle velocity: 960 m/s (HE-T, HEI-T); 850 m/s (AP-T); 1030 m/s AP(WC)
- Projectile types:
- AP-T weighting 72 g
- AP(WC) weighting 52 g
- HE weighting 57 g. HE filler: 2.8 g
MG 151/20 specifications
Two versions of the 20 mm MG 151 were built: one with a percussion priming system and a second E-model with electrical priming. Some rounds were available with a timer self-destruct and/or tracer (or glowtracer). There were also different types of high explosive shell fillings with either standard PETNPETN
Pentaerythritol tetranitrate , also known as PENT, PENTA, TEN, corpent, penthrite , is the nitrate ester of pentaerythritol. Penta refers to the five carbon atoms of the neopentane skeleton.PETN is most well known as an explosive...
, a mixture called HA41 (RDX
RDX
RDX, an initialism for Research Department Explosive, is an explosive nitroamine widely used in military and industrial applications. It was developed as an explosive which was more powerful than TNT, and it saw wide use in WWII. RDX is also known as cyclonite, hexogen , and T4...
and aluminium
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
), and a compressed version where more explosives were compressed into same space using large pressures (XM).
- Type: single-barrel automatic cannon
- Caliber: 20 mm x 82
- Operation: Recoil-operatedRecoil operationRecoil operation is an operating mechanism used in locked-breech, autoloading firearms. As the name implies, these actions use the force of recoil to provide energy to cycle the action...
; short recoil - Length: 1766 mm
- Barrel length: 1104 mm
- Rifling: 1 turn in 23
- Weight (complete): 42.7 kg
- Rate of fire: 750 rpm
- Effective range:
- Muzzle velocity: 805 m/s (M-Geschoss); 705 m/s (HE-T, AP)
- Round types:
Ammunition specifications
| German Designation | US Abbreviation | Projectile Weight [g] | Bursting charge [g] | Muzzle Velocity [m/s] | Description |
|---|---|---|---|---|---|
| Brandsprenggranatpatrone 151 mit L'spur ohne Zerleger | HEI-T | 113 | 2.3 g HE (Nitropenta PETN Pentaerythritol tetranitrate , also known as PENT, PENTA, TEN, corpent, penthrite , is the nitrate ester of pentaerythritol. Penta refers to the five carbon atoms of the neopentane skeleton.PETN is most well known as an explosive... ) + 2.1 g incendiary (Elektron Elektron (alloy) Elektron was a magnesium alloy developed in Germany during the First World War between 1914-18 as a substitute for aluminium alloy. Elektron is unusually light and has a specific gravity of about 1.8 compared with the 2.8 of aluminium alloy. Elektron was used to make incendiary bombs: the B-1E... ) |
705 | Nose fuze Fuze Fuze Beverage, commercially referred to as just Fuze , is a manufacturer of teas and non-carbonated fruit drinks enriched with vitamins. Currently the brand consists of five vitamin-infused lines: Slenderize, Refresh, Tea, Defensify, and Vitalize... , tracer, no self-destruct |
| Brandgranatpatrone 151 | incendiary | 117 | 6.6 to 7.3 g incendiary (BaNO3 Barium nitrate Barium nitrate with chemical formula Ba2 is a salt of barium and the nitrate ion.Barium nitrate exists as a white solid at room temperature. It is soluble in water, and like other soluble barium compounds, is toxic and should be handled with care... +Al+Mg) Magnesium Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole... |
? | Nose fuze |
| Minengeschosspatrone 151 ohne L'Spur | HE | 95 | 18.6 g HE (Nitropenta) | 805 | Nose fuze, no tracer |
| Panzergranatpatrone 151 mit L'spur ohne Zerleger | AP-T | 117 | none (bakelite filling in cavity) | 705 | No fuze, tracer, no self-destruct. Penetration 13mm steel at 60-degree impact, 100m range. |
| Panzersprenggranatpatrone 151 | APHE | 115 | 4 g HE (Nitropenta) | ? | Detonation after 5mm steel penetration. |
| Panzerbrandgranatpatrone (Phosphor) 151 ohne Zerleger | API | 115 | 3.6 g incendiary (WP) | 720 | No fuze, no self-destruct. Penetration 3 to 15mm of steel. |
| Panzerbrandgranatpatrone (Elektron) 151 ohne Zerleger | API | 117 | 6.2 g incendiary (Elektron) | 695 | Optimized for strafing unarmoured ships. No self-destruct. Penetration 15 mm of steel at 75-degree impact angle, 100 m range. Fuze functions after 4 mm steel penetration. |
See also
- WW2 Luftwaffe aircraft weapons
- Mk 108 30 mm cannonMK 108 cannonThe MK 108 was a 30 mm caliber autocannon manufactured in Germany during World War II by Rheinmetall-Borsig for use in aircraft.-Development:...
