MG 151: post-WWII use

The guns arming WWII warplanes were usually of limited general interest, just a component of the overall aircraft and leaving service with the planes they were installed in. Germany’s MG 151 on the other hand, had an extremely long and varied career after WWII, being used in any number of roles in the air, on the ground, and even on the sea; all around the world for many decades.

(MG 151 being serviced on a Luftwaffe fighter during WWII.)

(French MG 151 crew on a “Pirate”, or up-gunned H-34 Choctaw, during the Algerian War.) (photo via tenes.info website)

(Image from a 1980s South African VHS video promoting Vektor’s helicopter mount of the MG 151.)

during WWII

The original MG 151 (retroactively designated MG 151/15) aircraft gun fired a 15x96mm cartridge at 2,788fps – 3,379fps muzzle velocity depending on the ammunition type. Rate of fire was 740rpm and the effective range was 1,230yds.

As WWII began in 1939, the MG 151/15 was acceptable but unimpressive in combat. Waffenfabrik Mauser experimented with adapting it to more potent ammunition.

(Comparison of the older MG 151/15’s 15mm cartridge to the left, and the M-geschoss round of the definitive 20mm Mauser version of the MG 151.) (photo via Ruslan Musin)

The cartridge’s casing was necked out to accept a 20mm projectile, with the result being a 20x82mm round (2,641fps muzzle velocity). The new gun, which other than a shorter but heavier barrel and some minor alterations, was otherwise unchanged and was designated MG 151/20. It became “the default version” as WWII dragged on and was just called MG 151.

The 20mm MG 151 fired at 750rpm and had a range of around 800yds.

The new round itself was innovative. It was referred to as “2cm Minengeschoß” or M-geschoss. The M-geschoss projectile was made by drawing a hollow steel tube, rather than a casting. The result (besides being more expensive) was a 20mm HE round that was thin-skinned and light, with high internal volume. To this, a normal cast 20mm projectile would have had about 30% more explosive than the cast 15mm counterpart, but the drawn-metal M-geschoss had 600% more (18.7 grams of PETN).

(20mm MG 151 taken out of a He-162 Volksjäger fighter tested by France after WWII.)

During the latter part of WWII the MG 151 / M-geschoss combination was effective against British and American bombers, which often easily absorbed many dozens of 7.92 Mauser or 13mm rounds. The Luftwaffe calculated that only 18 hits from a MG 151 guaranteed destruction of a four-engined strategic bomber like the B-17 Flying Fortress, and even fewer might be sufficient.

(The USSR recovered some MG 151s during and after WWII but felt that their own 23mm designs were preferable.)

The MG 151 saw use on a wide variety of Axis warplanes during WWII.

(The Fw-190A-6 fighter had a pair of 20mm MG 151s in each wing plus two lighter machine guns over the engine cowling.)

(The He-177 Greif strategic bomber used a MG 151 as its tail gun.)

(The Do-335 Pfeil twin-engined fighter carried a pair of MG 151s.)

(There existed Rüstsätze, or field modification kits, to add MG 151 pods to German aircraft types. The Type VI for the Bf-109 fighter only detracted 5 kts off the plane’s airspeed.)

(Two ex-Lufthansa Ju-90 airliners were fitted with a MG 151 self-defense tail gun in Luftwaffe service. The top turret was a smaller MG 131.)

(The I-Hei version of the Imperial Japanese Army’s Ki-61 “Tony” fighter used MG 151s. Around 800 guns, along with some ammo and blueprints, were shipped via u-boat in 1943. This example was in the 244th Sentai which ended WWII at Yokaichi airbase in Japan. Other than the I-Hei version, most “Tony”s used Ho-5 20mm guns.)

(Italy’s Macchi C.205 Veltro fighter of WWII had a single MG 151 and two Italian machine guns.)

(Messerchmitt’s P.1101 jet fighter design was not completed before Germany surrendered in May 1945. Two weapon fits were proposed, either six MG 151s or four MK 108 30mm guns. A P.1101 prototype was shipped to Bell Aircraft in Buffalo, NY after WWII. This Bell photo (with part of the fuselage removed) shows planned locations of the MG 151s painted on the right side. The left side had a pair of painted-on MK 108s.)

(Germany also used trailer-mounted MG 151s in the ground-to-ground role during WWII. However the 20mm ammo of the MG 151 was not interchangeable with 20mm ammo for the more common FlaK 30/38 guns.)

(The Junkers EF 126 was a pulsejet fighter design not finished before WWII ended. It had two MG 151s under the nose. The EF 126 design was evaluated by the USSR after WWII.)

after WWII

FINLAND

Germany supplied Finland with 162 Bf-109 fighters of various versions during WWII, of which 102 survived the war and continued in use. Not all of the Finnish planes carried the MG 151 but Germany also provided Finland with numerous Rüstsätze kits containing the gun. As the Bf-109 became irrelevant as a fighter during the Cold War, MG 151s were reassembled into TorKK MG-151 twin anti-aircraft guns for use either aboard small warships, or ashore.

YUGOSLAVIA

The JNA, or Yugoslav Federal Army, used some MG 151s as SPAAGs (self-propelled anti-aircraft guns) during the late 1940s. These were carried in the bed of WWII trucks in a triple mounting with flash hiders added.

These were considered secondary weapons to FlaK 38 German 20mm guns leftover from WWII, and were withdrawn as newer AA weapons entered JNA service.

CZECHOSLOVAKIA / ISRAEL

After WWII, Avia in Czechoslovakia opted to restart production of the German Bf-109 fighter under the designation S-99. However the stockpile of Daimler-Benz DB 605 engines was destroyed by a warehouse fire shortly thereafter.

In a questionable decision, remaining Bf-109G airframes were mated with Jumo 211F engines not intended for this fighter. Furthermore as existing Messerschmitt propellers were running out, the broad-chord propeller of the He-111 bomber was substituted.

The result was a problem-plagued abomination designated S-199. The engine change precluded having a 20mm gun fire through the propeller spinner as on a normal Bf-109G, which would have left the S-199 with just two light machine guns atop the engine cowling. The Czechoslovak engineers added two MG 151s in underwing housings. The weight and drag of these made the S-199’s already-abyssmal performance even worse.

The S-199 had a brief career in the Czechoslovak air force but is better remembered as the Israeli air force’s first fighter. Twenty-three S-199s served the Israeli air force in 1948, scoring the nation’s first air-to-air victories. They were withdrawn in 1949.

UNITED STATES

The USA’s interaction with the MG 151 is perhaps most surprising of all. The United States typically was averse to foreign weapons during WWII, especially those of enemy origin, and it is even more surprising that the USA was still working with the MG 151 after WWII ended.

American interest in the MG 151 started completely apart from the German gun itself. Prior to entering WWII in 1941, the US Army was considering a light anti-tank rifle. The gun project, designated T1, and ammunition project, designated T32, were separate but related projects.

The T1 gun was cancelled but in the meantime, development of the T32 ammunition had already been completed. It was a .60cal / 15.2x114mm cartridge.

(WWII ammo box for the T32 .60cal ball cartridge. These are highly collectible today; a relic of ammunition which never saw combat.) (photo via IMA-USA)

As the .60cal cartridge still existed, in 1942 an attempt was made to adapt it for airborne use, in a highly-modified M1 20mm gun. The work was done by Eclipse Machine, a division of the Bendix corporation. The goal was an aircraft weapon causing heavier damage than the .50cal Browning machine gun, but still with a useful rate of fire. This project ended in failure.

The US Army Air Corps and US Navy both still realized that eventually sometime down the road, something would replace the .50cal AN/M2 on American fighters. So interest in the .60cal cartridge continued.

In 1942, Great Britain presented a MG 151 taken from a downed Luftwaffe plane to American intelligence. In September 1942, a decision was made to reverse-engineer the MG 151 but for use with the American .60cal cartridge.

The MG 151, designated T17, was reverse-engineered by Colt Firearms. As the Luftwaffe 20mm feed links would be useless with the .60cal ammo, the Autoyre company in Connecticut (which made magazines for the M1 carbine during WWII) designed a new belt. The prototype T17 was built by Frigidaire (of kitchen appliance fame) in conjunction with Springfield Armory. Frigidaire’s Ohio factory was planned as the main production point when the gun entered service.

To reverse-engineer the MG 151 was little trouble for Colt gunsmiths as the German weapon was logical and surprisingly uncomplicated. The rechambering from Mauser’s 20mm to the .60cal’s 15.2mm meant resizing the receiver and barrel. Colt also lengthened the bolt and extended the feedway. Otherwise the T17 was little different than the German MG 151.

(.60cal ammunition and links for the American near-clone of the German 20mm gun.)

Only two months after Colt began the project, the first prototype T17 was test-fired in Connecticut. The recoil was heavier than anticipated, and would likely cause problems to aluminum structure-box wings. The rate of fire was also higher than desired. A dampener was quickly designed but failed to fully rectify the issues.

None the less in 1943 ten pre-production T17E1 .60cal guns were ordered from Frigidaire. These would have a 800rpm rate of fire. After firing 70 rounds at Aberdeen Proving Grounds that year, one of the T17E1s exploded.

Frigidaire identified the issue as using SAE 1060 steel in the T17E1. This is a very common steel in American industry, and was used successfully on numerous other WWII firearms. The US Army ordered two new pre-production guns, designated T17E2, using SAE 4640 alloy.

The two T17E2s were tested at Aberdeen Proving Ground in late 1943. They fired a combined 1,027 .60cal rounds, with continued problems.

Oddly enough, with the basic MG 151 already reverse-engineered, no consideration was given to simply also reverse-engineering the 20mm Mauser cartridge and using it to immediately get the weapon into the war. The US Army wanted to stick with its .60cal cartridge.

Instead another modification, the T17E3, was ordered. Even though the T17E2 had issues and the T17E3 had not even been tested, interest was still very strong. In December 1943 the US Navy ordered 2,500 guns followed by 5,025 for the US Army Air Corps. Ammunition production also ramped up.

The first two T17E3s got off to a rough start in December 1943, with one being destroyed. During 1944 jams were reduced to 1% of chambered rounds which was not spectacular but headed in the right direction.

Just as things looked to be going better, an independent test of three T17E3s at Rock Island Arsenal was judged poorly, with the guns having erratic rates of fire and requiring replacement of eleven key parts after 2,000 rounds, which would be unsustainable in the Pacific theatre. Particularly the firing pin was rated only to 1,000rds.

In 1945 some components were redesigned with improved performance. WWII ended on 2 September 1945. By then, 309 guns and six million .60cal rounds had been produced.

(North American Aviation started its private NA-135 jet fighter concept during the final months of WWII. This was one of the types considered for the MG 151 clone, but was instead armed with the trusty WWII .50cal Browning. Only 30 of these planes, designated FJ-1 Fury, were ordered in 1946. Only one WWII-veteran aircraft carrier, USS Boxer (CV-21) ever took them to sea. By 1949 they were already reassigned to shore bases and were retired in 1953. The nickname was recycled for the more successful F-1 Fury.)

Shortly after WWII ended, a P-38 Lightning was experimentally fitted with T17s. The results were mediocre at best.

In 1946 additional tests were done as the T17E5, which the US Army planned to use as an AA gun aboard future tanks. However, budget cuts ended all T17-series production with the weapon still not fully approved for either aircraft or ground use.

Even with production cancelled, the Defense Department kept this project alive and retained the .60cal ammunition made during WWII.

In retrospect now, it’s hard to say what exactly the Pentagon was thinking by this point. The logic behind copying the MG 151 in 1942 was to get a new gun into WWII faster than could be accomplished by designing one from scratch. By September 1946, not only had that not happened but the entire war had already been over for a year.

In 1947, a radical “do-over” of the whole MG 151 cloning was done, with the bolt, receiver, and barrel all being changed. The new weapon, designated T51, was only 4’4″ long and was more compact throughout, as it was anticipated that future jets would have wings too thin to put guns in and that they would need to be sited inside the fuselage.

By this point “the wheel had fully turned” and so little of the T51 was still a MG 151, that it would have been better just to start over from scratch altogether. The T51 project was also cancelled and by the decade’s end, the United States had finally lost interest into cloning the MG 151.

(A mockup of the T51)

As a side note the .60cal cartridge refused to die and was still a concept in the 1950s and 1960s, including being a candidate cartridge for early concepts of General Electric’s Vulcan gatling-style gun. None of these ideas were successful and the .60cal was never used.

FRANCE

France was perhaps the main post-WWII user of the MG 151, putting the German gun into every imaginable type of role – aircraft, ground vehicles, and even warships.

France recovered some MG 151s from wrecked or abandoned Luftwaffe aircraft inside France even as WWII was still ongoing.

(After the tank factory at Fouga was liberated in 1945, some Lorraine 37L artillery tractors were fitted with a makeshift armored tower and captured MG 151. Free French troops used them until the Germans were pushed fully out of France. The Lorraine 37L, a pre-WWII design, quickly fell out of use. France tried and failed to sell all that survived WWII to Switzerland in 1946 and doled out a few to Syria in the late 1940s.)

After WWII, cleanups of ex-Luftwaffe airfields in the French occupation zone of Germany yielded many more MG 151s. The French zone also included the Mauser Werke factory at Oberndorf which had been overrun by the US Army in 1945.

France readily used ex-German weapons after WWII; be it machine guns, tanks, planes, and even u-boats. France also successfully copied several Luftwaffe designs after WWII, notably the AAC.1, a copy of the Ju-52 transport. Meanwhile the French aerospace industry experimented with combinations of Luftwaffe technology: engines, guns, and radars; in new French airframes.

(SO.8000 Narval)

SNCASO’s SO.8000 Narval was a post-WWII French fighter project armed with MG 151s and powered by an Arsenal 12HO2, the French copy of the Jumo 213. Already obsolete on the drawing board, only two Narvals were made in 1949 and the project was terminated in 1950.

France’s war in Indochina, which began soon after WWII ended, provided an opportunity to use the MG 151 in a maritime setting.

(LCM riverine combatant conversion in Indochina. The crow’s nest was every bit as vulnerable to Viet Minh rifle fire as one might expect, and this feature was later eliminated.)

In 1951 two WWII American Mk6 landing craft (LCM) were modified into “river monitors” to patrol the Mekong, Red, and Saigon river networks. They had the bow door welded shut and plated over, a roof added onto the former troop bay, and steel armor added to the wheelhouse. The main armament was turrets taken off of WWII British Coventry armored cars and modified. The Coventry’s  2-Pounder gun was retained but the coaxial gun was changed to a MG 151, which fit into the spot for the BESA coaxial machine gun and delivered superior firepower. On these boats, a second German MG 151 in an open mount was astern behind the wheelhouse. Other assorted WWII weapons such as British Bren machine guns or French Mle. 27/31 mortars were added as well.

(Close up photo of the modified Coventry turret with the MG 151 alongside the 2-Pounder main gun.)

These were successful and by the end of the Indochina War, fourteen had been made. One was sunk on the Black River near Hanoi by recoilless rifle fire from the riverbank, but otherwise they were a force to be reckoned with. During the Vietnam War the United States made many similar conversions of various styles; but none with any foreign weaponry.

(photo via indochine54 website)

The vessels above are EAs, or “engine d’assaut” (“assaulting vehicles” in English) of which eighteen were built in Saigon between 1950 – 1953. After WWII, the United States provided France with blueprints for the LCVP landing craft design. The EAs differed in being all steel instead of mixed metal / wood as in the WWII American LCVPs. They were powered by a Gray 64HN9 marine diesel, of which the USA had hundreds surplus after WWII. They were 35′ long but had a draught of only 3’6″, making them very suitable for riverine use. They could obviously survive being beached. The EAs were armed with a MG 151 inside a steel gunshield as seen above and below.

The EAs were not as successful as hoped. The WWII German gun brought a lot of firepower to a small rivercraft, but the original LCVP of WWII was only meant to ferry troops from a transport ship to the invasion beach. They were not intended to be occupied for prolonged periods and were not pleasant to be aboard. While the hullform was not “flawed”, they behaved in the water much differently than say, a motor punt or pinnace of equal size, and took a skilled coxswain to control.

For France, sending ex-Luftwaffe MG 151s to Indochina had few drawbacks. They were good guns, they were free, and they didn’t decrease the amount of American-made or French-made guns available for NATO commitments in Europe.

Meanwhile these ex-German guns had a new prospective role on the AMX-50. Development of this tank began several weeks after the end of WWII in 1945. During its long development, various main guns (90mm, 100mm, and 120mm) were proposed, all using an oscillating turret. For the secondary and/or coaxial weapon, the MG 151 was proposed. The French considered the WWII Luftwaffe weapon to have superior firepower to a machine gun while filling a comparable “footprint” inside the tank.

As the AMX-50’s development continued, the MG 151 was considered for placement in a traditional coaxial position; in an off-level spot with a smaller AA-52 7.5mm being coaxial; or omitted altogether; and (in the final design) housed in a duplex mount atop the turret, where a MG 151 would be controlled by the tank commander from his cupola with a M2HB .50cal on an independently-rotating ring mount above it.

The AMX-50 tank went through a 10-year design cycle and in the end, was never put into production.

During France’s Algeria War, GHAN-1 (1st Naval Helicopters Group) in north Africa experimented with mounting a MG 151 on a Citroën 2CV utility car.

The objective was two-fold; to supplement the WWII American M8 Greyhound armored cars in the airbase security role, and as a fire support vehicle which could be carried underslung by a helicopter. The mounting could be swapped to take a M20 75mm recoilless rifle instead of the MG 151 if desired.

The MG 151’s recoil was such that the two tires on the downrange side of the 2CV momentarily left the ground during firing. Otherwise this gun was successful aboard the 2CV but the idea was not widely adopted.

In the immediate aftermath of WWII, everything in France’s MG 151 stockpile: guns, replacement barrels, mountings, ammunition, and links; were all German-made. As years went on, and France continued to use the ex-Luftwaffe weapon, this became unsustainable.

The first need was replacement links. These were developed by the SIPR company (today, Eurolinks) as the 20L-61-6. The SFM company cloned the M-geschoss ammunition. As far as the actual gun, first the barrel (and later the bolt, and later still the whole weapon) were made by Matra, a French defense company formed after the liberation in 1945. (In 1999, Matra was merged into Aérospatiale which in turn merged with Airbus in 2017. Ironically Airbus in 2022 also includes the corporate legacies of Messerschmitt and Dornier; who made some of the MG 151’s carrying warplanes during WWII.)

Matra also developed a modern flexible mounting for the WWII German 20mm gun.

(The French experimented with several ways to use the Matra mount for the MG 151. This version fed right to left from an ammo box that moved with the gun. The mount was set on a sponson installation outboard of a helicopter’s cabin.)

(This version, photographed in 1962, had the MG 151 in an a depressed-elevation pintle inside the cabin, feeding from a larger ammo box in the former copilot position. The mount has a more sturdy chassis with yoke-style trigger and deflection gunsight. This was the definitive version.)

France’s interest in this field started in a most unofficial way. During the early part of the Algerian War France’s main helicopter types were the little Bell 47 and the larger Sikorsky H-34 Choctaw.

A problem for the French (which the USA would later deal with in Vietnam, likewise the Soviets in Afghanistan) was the cost of bringing military aviation to bear against small groups of rag-tag guerillas in rural settings. In terms of fuel expended, maintenance required, and ordnance used; the ratio of money-per-flight hour was expensive when using fixed-wing WWII aircraft like the Corsair, which made a single firing pass and returned to base.

In 1957 Col. Felix Brunet, with no authorization or supervision, modified a H-34 into the “Mammouth”. He tried a variety of weapons including recoilless rifles, rockets, machine guns, and ten WWII American 250 lbs bombs.

Brunet’s superiors were not thrilled when they learned of the Mammouth and he was charged with unauthorized alterations to an aircraft and misappropriation of funds. Col. Brunet was placed on restriction pending a possible court-martial.

When General Edmond Jouhaud learned of the matter, he made the disciplinary charges “go away” and told Brunet to continue his experiments.

The next concept was the “Pirate”, a H-34 armed with two MG 151s in the doors and two M2HB Browning .50cals in the cabin windows.

The first Pirate entered combat in 1957 and was quite successful, with the 20mm gunfire from the WWII German guns being considerable.

(The Pirate used the new Matra mount for the MG 151. The gunshield initially installed was found to be an annoyance and discarded.)

A series conversion project followed and the French navy also made a few. Typically an escorted insertion mission during the Algerian War had one Pirate with two standard H-34s.

The French army bought 98 Piasecki H-21 Shawnee twin-rotor helicopters from the United States between 1955 – 1958, plus 10 delivered to the French navy. These were widely used during the Algerian War. Within the American military H-21s were commonly nicknamed “Flying Bananas”. This nickname crossed the Atlantic as “de Bananes”.

The H-21 was tremendously useful as a transport but highly vulnerable, as it came completely unarmed. In 1957, a series of experiments were done as to converting some into helicopter gunships.

(An early experimental fit was a rack on the forward landing gear, mounting two M1919 .30-06 machine guns, two M2 Browning .50cals, and eight air-to-surface rockets.)

No fewer than four different fits were tried. In the end the final fit was two twin 7.5mm machine gun pods, two Matra-116 unguided 19-round 68mm rocket pods, and an optional MG 151 in the door.

Seven French Flying Bananas were so converted. They served for only about a year as the results were mixed. In some situations they were useful, but the H-21 was about as far away from a nimble helicopter as could be imagined and the weight of all the weapons and ammunition loaded them as much or more than a passenger detail would. The MG 151 pintle was often replaced by a lighter machine gun. The French army viewed the H-21 gunships as unnecessary.

Meanwhile the French navy took the opposite approach, using the heavy MG 151 in the door mount position on their H-21s in Algeria but omitting everything else.

(France used the AAC.1 Toucan, the post-WWII copy of the Junkers Ju-52, heavily in Algeria. At one point it was considered to arm some with a MG 151 in the cargo door but this was not proceeded with.)

After the Algerian War the main carrier of the MG 151 in France was the Alouette III helicopter. A follow-on to the successful Alouette II, the Alouette III was widely used by France and was also a tremendous export hit. Several users (including France) armed some with the MG 151 on the Matra door mount.

(Malaysian Alouette III in the late 1970s. Malaysia was one of the export customers who also selected the MG 151 option. This Alouette III was a MG 151 gunship, as evidenced by the removal of the left front dashboard and copilot’s seat to make room for the 20mm ammunition.)

(The alternative option to the MG 151 which France considered for a 1960s helicopter door gun was a twin version of the obsolete MAC 34 machine gun of WWII, on a new mounting as seen in the upper photo.)

The SA.3164 was a proposed attack helicopter of the late 1960s and early 1970s. It was armed with a MG 151 in a flexible nose mount with 480rds of ammo, plus four SS.11 anti-tank missiles. France did not put it into production and it found no export customers.

The SA.3164 was the final “new” application of the WWII German gun by France, but Matra was selling and supporting the MG 151 abroad, with some of the users employing it in combat.

ARGENTINA

After WWII, Argentina purchased thirty G.55A Centauro fighters from Italy. These had been assembled after WWII ended using Fiat’s wartime tooling (and even some leftover incomplete airframes). They were armed with three MG 151s.

The MG 151 appeared again later in Argentine service, in the form of helicopter door guns using the postwar French mounting. It is unclear if the actual guns were WWII weapons stripped off the retired Centauros, or if both the new mount and gun as well were French-made.

(MG 151 door gun of an Argentine S-58T naval helicopter. This was a turboshaft-powered derivative of the piston-engined H-34 Choctaw.)

The last Argentine application of this WWII German gun was a 1980s Argentine navy project for a modular weapons fit to the SA.316 Alouette III multipurpose light helicopter; fourteen of which had been imported from France prior to the 1982 Falklands War.

(photo via fuerzasnavales web forum)

Among the late Cold War-era applications of the MG 151, this was unique in that it was a fixed, forward-firing use of the WWII weapon. The Argentine Alouette package had a MG 151 on the helicopter’s right side, fed from an ammunition box inside the cabin replacing the right rear seat. The gunner sat in the left rear position. The MG 151 was set upon a removable chassis external to the airframe. When removed, the SA.316 could instead carry AS.11 missiles, or one A-244S anti-submarine torpedo, or LAU-32 rocket pods. The modular system project ran into budgetary problems and in any case, Argentina retired the last naval SA.316 in 2010.

PORTUGAL

During the late 1960s and early 1970s, Portugal was simultaneously fighting three colonial wars in Africa: Portuguese Guiné (today Guinea-Bissau), Angola, and Mozambique.

Portugal was already using the basic Alouette III as a scout and troop transport, so the Matra MG 151 gunship conversion was the next step.

(A standard transport Alouette III in Portuguese use in Africa. The “elephant ear” filters protected the engine intakes. The soldier in the door has an AR-10.)

(Portuguese MG 151 gunship conversion. These were called “lobo mau” (“bad wolf”) in Africa.)

Portugal used the post-WWII French MG 151 mounting, with the gun fed from an ammo box occupying the former spot of the left front cockpit seat.

Portugal found the MG 151 ideal for counter-guerilla warfare in Africa. The 20mm rounds had greater penetration through tree cover. One aspect commented on positively was that when firing into buffalo grass, the impacts left “puffs” which allowed the door gunner to accurately spot their impact better than 50BMG or 7.62 NATO rounds.

(Portuguese MG 151 Alouette gunship in the Guiné theatre, an especially difficult climate to fight a modern war in.)

Portugal developed tactics which would be later used by other MG 151 operators on the African continent. The MG 151 gunship operated with two or three non-converted Alouette “troopships”. En route to the LZ the gunship acted as the flight leader, and then provided cover during the operation.

Portugal abandoned its colonies in 1975, ending the three wars. MG 151s in the Portuguese military had been more or less intended for these conflicts but some did remain in use in Portugal proper into the 1980s.

RHODESIA

Rhodesia (today Zimbabwe) was another MG 151 user after WWII. The “Bush War” began in the late 1960s but accelerated from 1972 onwards, until the conflict’s end in 1979.

(Rhodesian Alouette III / MG 151 combination, aka “K-Car”. This helicopter has the elephant ear filters and also the Strela Shroud, discussed later.)

(The Alouette was ingrained into the Rhodesian military’s entire structure throughout the nation’s brief lifespan. Here, recruits at boot camp practice rapid embarking and disembarking a mock-up Alouette fuselage.)

In the early stages of the war Alouettes were organized into “penny packets” of two or three aircraft, sometimes with one of them having an improvised machine gun mount, sometimes not.

As the war carried on, a highly-refined set of tactics called Fire Force was developed. An attack and command helicopter (similar to the Portuguese concept) was fitted with the MG 151 and called the K-Car. The K-Car had the MG 151 mount in the left rear door, feeding left-to-right from an ammunition box in the Alouette III’s baggage hold immediately behind the left side of the cabin.

On the K-Cars, only three men were aboard: the pilot, the door gunner, and the Fire Force commander, who sat in a backwards-facing armored seat behind the pilot.

Normal Alouettes were called G-Cars. They carried the pilot and sometimes a door machine gunner on the left side, plus a four-man infantry squad. Some G-Cars were unarmed.

In a G-Car, there were two infantrymen facing backwards next to the pilot, and two more to the right of the door gunner. The squad automatic weaponman always sat on the door and (other than the gunner) was the only man allowed to fire out of the helicopter in flight. The door guns of the G-Cars varied, above is shown a twin mount for WWII American M1919 machine guns. Others had a FN-Herstal 7.62mm machine gun and some had no door gun at all. Each infantry detachment was called a “stick”.

(Rhodesian G-Car with a stick.)

The Fire Force concept was one K-Car armed with the MG 151, three G-Cars, a single fixed-wing warplane on standby, and if the situation required a single paratrooper detachment aboard a Dakota, the WWII nickname for C-47 Skytrains lend-leased to Great Britain.

(K-Car Alouette III armed with a MG 151 in front of a WWII Dakota (C-47 Skytrain) in 1970s Rhodesia.)

The ZAPU and ZANU guerillas were sometimes armed with Soviet-made SA-7 “Grail” shoulder-fired surface-to-air missiles, which used infrared homing (“heat-seeking”) guidance. Rhodesia equipped many Alouettes, both K-Cars and G-Cars, with Strela Shrouds. These were simple metal shapes around the turbine exhaust which directed its heat upwards into the rotor’s downwash. The seekers on early versions of the SA-7 missile were not great and this crude device was often sufficient to protect the helicopters.

(Strela Shroud on a Rhodesian K-Car Alouette.)

The ultimate application of this concept was the Jumbo Fire Force, which had two K-Cars with MG 151s, eight G-Cars, two fixed-wing warplanes, and the Dakota with paratrooper detachment.

The WWII German weapon was highly effective in 1970s Rhodesia. The K-Car would orbit about 300′ above the battle, making a tight counterclockwise turn. The MG 151 gunner used short bursts.

During the conflict, South Africa and Rhodesia cooperated and the MG 151 concept migrated to that country, which also flew Alouette IIIs and was also fighting a war.

SOUTH AFRICA

(South African Alouette III armed with a MG 151 during the late 1980s/early 1990s.)

After Portugal left Angola in 1975, South Africa began fighting a border war against guerillas across the southern Angolan border and inside the northern border of SWA (South-West Africa; today the country of Namibia). SWA was an “accident of history”; originally Germany’s pre-World War One colony of Sudwest Afrika, it was awarded to South Africa as a temporary mandate. By the 1970s SWA was technically a separate entity but was more or less viewed as a permanent protectorate in South Africa.

(South African MG 151 gunship at Swartkops airbase in 1992.)

South Africa observed the positive results the Portuguese and Rhodesians obtained with the MG 151 / Alouette III combination. South Africa already had purchased the same helicopter type from France, and also purchased some Matra-made MG 151s along with blueprints. After the 1977 total arms embargo, the gun and ammunition were made locally.

The ammunition was manufactured by Pretoria Pressings in South Africa. The complete MG 151 and Matra-designed mount was manufactured by Vektor, a division of the Denel company. The installation process is shown below.

(South African Alouette III with the copilot’s seat removed, left rear door removed, a small rounded fuselage structure section below it removed, and the baggage compartment open.)

(A portion of the floor was removed, and a sheet metal buffer plate installed in the missing fuselage structure area.)

(A steel baseplate with the pintle was installed into the opened area of floor. A metal kickplate was installed around the pilot area to prevent the MG 151 gunner from accidentally bumping the helicopter’s controls.)

(The Matra housing was set into the pintle. Next, as shown here, the MG 151 less barrel was put into the housing.)

South African MG 151 gunships carried a spare barrel, and its holder had a second empty slot so that the gunner could optionally remove the in-use barrel while in non-combat flight to preclude it sticking out of the helicopter.

(The finished installation with complete MG 151. In the South African application, it fed left-to-right from an ammo box behind a light armor plate inside the baggage compartment. The canvas bag collected spent cartridges.)

Since the MG 151 is electrically fired, the South African version had STANAG-compliant cables which fed into the Alouette III’s electrical system with no modifications or adapters needed.

(South African-made MG 151s retained the French-style deflection gunsight.)

Towards the end of the apartheid era, South Africa began work on a successor gun still based on the WWII German MG 151.

Vektor’s GA-1 uses the same operating system but a new cartridge. Supposedly derived from a General Dynamics M55A2 20mm training round used on the F-16 Falcon and F/A-18 Hornet and obtained by unknown means, the GA-1’s ammunition is a new 20×146.5mm cartridge.

(Pretoria Pressings offers this ammunition in semi-armor piercing, HE, HE-Tracer, and training variants.)

The GA-1’s ammunition is sized to be compatible with NATO-standard handling equipment. The muzzle velocity is 2,362fps. The overall operating principles of the WWII German weapon remain.

The GA-1 can be converted to fire 50BMG ammunition via a parts kit that swaps out the barrel and bolt and adds a feed plate adapter. Oddly enough, it does not appear that any kit was manufactured to adapt the GA-1 to the MG 151’s WWII M-geschoss round.

(The lone XH-1 Alpha technology demonstrator helicopter had a GA-1 in a servo-powered undernose mounting.)

GA-1s began entering South African service at the end of the 1980s. This weapon slipped in importance dramatically in 1993 with the end of apartheid. South Africa was again free to buy weapons abroad, at the same time the military budget at home was being cut in line with much-decreased threats to the north. None the less, as of 2022 Denel Land Systems still offers the GA-1 via “production as required” availability. The last known customer was the Indonesian navy, which selected the GA-1 for a shipboard light gun in 2010.

postscript

In the three quarters of a century since the MG 151 was first fielded, any number of newer 20mm guns have come and gone and it is a bit surprising that this WWII weapon endured as long as it did. It is extremely unlikely that it will be further developed beyond the GA-1 of the late 1980s.

Surprisingly there was one last gun developed to use the WWII German M-geschoss cartridge. The Vidhwansak is an anti-material rifle used by India’s Border Security Force. This bolt-action rifle has a three-round magazine and can use either 20mm M-geschoss, 12.7x108mm Soviet, or 14.5x114mm Soviet ammunition. A Vidhwansak can be changed between the three in a two minutes by one man using tools included with the rifle. The Vidhwansak entered service in 2010 and will likely be the last new firearm designed for the WWII German M-geschoss round.