# Machine gun 42

Machine gun 42
general information
Military designation: MG 42
Country of operation: German Empire
Developer / Manufacturer: Großfuß , MAGET , Mauser ,
Steyr-Daimler-Puch ,
Wilhelm Gustloff Werke
Development year: 1942
Manufacturer country: German Empire
Weapon Category: Machine gun
Furnishing
Overall length: 1230 mm
Sight length : 430 mm
Technical specifications
Caliber : 7.92 x 57 mm
Possible magazine fillings : 50 rounds, 120 cartridges
Ammunition supply : Ammunition belt
Cadence : 1200-1500 rounds / min
Fire types: Continuous fire
Number of trains : 4/6
Twist : right
Visor : open sliding visor , rising 200–2000 m 100 m
Closure : Roller lock
Lists on the subject

The MG 42 (actually universal machine gun model 42 ) is a machine gun in caliber mm 7.92 × 57 , that of the German Wehrmacht in World War II was used.

The weapon was introduced in 1942 after the Army Weapons Office was looking for a successor to the MG 34 , the production of which was complex and cost-intensive. The newly developed MG 42, designed for mass production using the sheet metal stamping process, was designed in such a way that it could be used by the crews familiar with the predecessor weapon without any problems. The MG 34/41  - an improved and simplified version of the MG 34 - did not go into series production.

## history

The MG 42 was designed by Werner Gruner , who worked as a technician at the metal and lacquerware factory Johannes Großfuß near Döbeln in Saxony . Gruner was not a weapons specialist, but a specialist in series production, especially in the sheet metal stamping process . He was presumably supported by specialists in the locking system. It is unknown who designed the MG 42 roller lock and whether this design was derived from other types of locking.

### manufacturing engineering

The MG was primarily from stamped and formed parts produced. Only the most important parts were elaborately milled from solid steel. This enabled the weapon to be produced quickly, cheaply and in large quantities. The somewhat primitive and unclean-looking welding of the parts led the Allies , who captured the first specimens in North Africa, to believe that Germany had problems with the manufacture of infantry weapons. The MG 42, however, represented a milestone in weapon production in that it was the first firearm mainly manufactured using sheet metal stamping technology. While the price of the MG 34 was 310  RM (equivalent to 1,230 euros today), the MG 42 could be produced for only 250 RM (990 euros). The production time could be reduced from 150 to 75 working hours.

### properties

Paratroopers with MG 42 on tripod, 1944

The MG 42 demonstrated high reliability, even in bad weather conditions, with a good shot accuracy. The ammunition used was the 7.92 × 57 mm rifle cartridge (also known as 8 × 57 IS), which was also used for the Wehrmacht Mauser 98k carbine .

The MG 42 could be used both stationary and mobile. Stationary it was used, among other things, in the bunkers of Normandy to repel the invasion, while mobile it was mostly led by tank grenadiers . The MG was equipped with a bipod as standard, which could be attached to the housing at two different points. The front was the usual point for the greatest accuracy, the attachment in the middle of the weapon allowed a larger swivel range with limited accuracy. Each MG 42 could also be mounted on a field tripod and was then referred to as a "heavy MG", without it as a "light MG".

The butt has a shoulder-shaped support and a grip option so that the weapon can be held steadily when firing.

Through a simple door on the right side of the running casing could run be replaced within seconds, which was necessary due to the strong heating during prolonged fire. The MG troops carried up to five replacement runs. The later production series had hard chrome-plated barrels and mechanisms as a major improvement , which considerably reduced wear.

The MG 42 reached a high for infantry weapons cadence of 1500 shots / min, so 25 shots / sec. This high rate of fire also predestined the weapon for air defense ; in the infantry, the high consumption of ammunition was also criticized, although the effectiveness was high.

### Nicknames

The MG 42 could be recognized acoustically by the rattle of its bursts of fire, as the noises of the individual shots merged into one another. It was therefore also called "electric MG". The Western Allies, especially the British, called the MG 42 as well as the MG 34 "Spandau". This probably went back to the MG 08 of the First World War, on whose nameplates the word “Spandau” was written, if these were manufactured in the rifle factory Spandau . MG 42s, however, were not manufactured in the former Prussian rifle factory Spandau near Berlin. The German soldiers gave the MG 42 nicknames like “Hitler's saw”, “Singing saw” or “bone saw”. The term "Hitler's scythe" is also often to be found, which results from the similarities between the firing technique used by the machine gunner and the swinging movement of the harvesting tool when it is used. The term “Hitler violin” continued to circulate based on the “ Stalin organ”. The term "Hitler's Buzzsaw" for the MG 42 is still known to the American population today.

### Further developments

Bundeswehr soldiers with MG1 (1960)
German soldier with MG 42 (1944)

The MG 42 was also delivered to countries allied with the German Reich during World War II , such as Finland , the Social Republic of Italy , Slovakia and Hungary . Towards the end of the war, the successor MG 45 was produced in very small numbers. This model received a movably supported roller lock (mass ratio lock) and a fixed barrel similar to that of the G3 and the HK21E .

The machine gun was used as a fully developed weapon after the war with only a few changes from 1951 at the Federal Border Police , in the Bundeswehr as MG1 (new builds adapted to 7.62 × 51 mm NATO ammunition, from 1956) or MG2 (after conversion to the NATO standard cartridge 7.62 × 51 mm, introduced from 1965). In 1969 the MG 42 was fundamentally revised again and introduced into the Bundeswehr as MG3 . Until the mid-1970s, units of the riot police were also equipped with it. Only details on the breech, barrel, housing, dust cover, bipod, recoil amplifier and the caliber of the weapon have been changed. In West Germany and Austria, old stocks of the MG 42 were converted to the NATO cartridge 7.62 × 51 mm (barrel, cover, belt cover and return spring) and continued to be referred to as MG 42. The most important change was a heavier slide and the installation of a slide brake, which reduced the theoretical rate of fire to 1200 rounds per minute in order to reduce barrel wear and ammunition consumption.

Numerous other armies also use this type, for example Italy (MG 42/59), Austria (MG 42/59 and later MG 74 ) and Pakistan (MG 3). The MG 51 introduced in Switzerland was also a variant of the MG 42 adapted to the requirements of the Swiss Army. The support rollers were replaced by support flaps and the rate of fire was limited to 1000 rounds / min. The M42 / M53 called šarac was developed in Yugoslavia .

After World War II, the US Army largely adopted the MG 42 feed mechanism for its M60 machine gun .

## construction

Different versions of the MG 42 in the Munster tank museum . On the right behind the flying tripod, below with a mount as an sMG

The MG consists of the following assemblies:

1. casing
2. Base piece with buffer, closing spring and shoulder rest
3. Lid with belt feeder upper part
4. Tube (barrel)
5. Clasp (also called lock)
6. Recoil booster
7. Pipe guide sleeve
8. Handle with trigger
9. Bipod

1. The housing accommodates the barrel and breech, serves to guide the barrel and breech, protects the inside of the weapon against damage and contamination and connects all parts into a whole. It is cold-pressed from stable sheet steel using stamping technology. The surface is protected from corrosion and scaling by browning . The front part of the housing, which encompasses the barrel, is provided with openings for better heat dissipation. A threaded barrel guide bushing for the recoil booster is pressed into the front end. The bottom piece is inserted into the rear end. On the top there is a groove for receiving the roller bolt and an opening for cartridge feed. The underside has an opening for the trigger and an ejection window for ejecting the case. The ejection window can be closed by a springy dust cover. The tube change flap is attached to the right-hand side, through which the rear end of the barrel can be swiveled out to the side and the barrel pulled back out of the housing. The two guide rails and the curve piece are riveted inside the housing. A sliding visor from 200 to 2000 meters, increasing every hundred meters, and a foldable anti-aircraft visor are attached to the housing.

2. The bottom piece closes the housing to the rear and takes the locking buffer. The lock buffer is used to brake the lock and is used as an abutment for the recoil spring and ejector bushing. The shoulder rest is screwed onto the bayonet thread of the base piece.

3. The lid closes the weapon at the top and takes the upper part of the belt feeder with the switching elements (transport lever, connecting lever and belt slide) for feeding the cartridge belt. It can be folded forward and up around a cover bolt. Under the cover is the lower part of the feeder, which guides the cartridge belt and aligns the cartridge to be fed by means of a stop.

4. The tube is used to guide the projectile. The cartridge is ignited in the chamber and supported while the pressure is being built up. The drawn part has four helical grooves, which are called trains in weapons technology . The trains cause the projectile to rotate rapidly around its longitudinal axis. This twist stabilizes the projectile on its trajectory similar to a top. A thread is cut on the rear end of the barrel. It is used to screw on the locking piece. The front end has a collar to guide the barrel.

5. The lock is a support roller lock . It essentially consists of two parts, the bolt housing and the bolt head. The two locking rollers and the extractor are located on the bolt head. The sliding ejector sleeve and the transport bolt are attached to the lock housing. Firing pin holder, firing pin, ejector and ejector rod are loosely inserted. The lock causes the cartridge to be ejected from the cartridge belt, the cartridge to be inserted into the chamber, the cartridge to ignite, the cartridge case to be pulled out and the cartridge case to be ejected. Shortly before the shot is released, it locks with the locking piece and closes the barrel to the rear. In addition, the lock drives the feed mechanism in the lid via the transport bolt.

6. The recoil booster causes a steep build-up of pressure in front of the muzzle. This significantly increases the recoil of the barrel and breech and ensures quick and safe unlocking after the shot. It consists of three parts: the actual recoil amplifier with flash hider , recoil nozzle and barrel guide sleeve. The funnel-shaped flash hider causes divergence, turbulence and faster cooling to significantly weaken the flash.

7. The pistol-shaped handle accommodates the trigger mechanism and is used for easy handling of the weapon when firing. It has a simple but effective slide lock. The weapon can normally only be secured when cocked. Setting to single fire is not possible.

8. The bipod is used for the front and middle support of the weapon. It can be folded up on the housing.

## function

MG 42 / MG 3 in closed locking position

The MG 42 is an open firing weapon. This means that there is no cartridge in the chamber before the shot and the slide is at the back. The weapon is open before the trigger is pulled. Because the cartridge chamber is empty, there is no danger of self-ignition and the barrel is easier to cool through the air flow.

In order to finish loading the weapon and make it ready to fire, the shooter has to pull the slide with the cocking slide backwards as far as it will go. The lock is unlocked and the closing spring is tensioned. If the dust cover is closed, it will be opened by the retracting lock. Then the shooter pushes the cocking slide forwards as far as it will go, the cocking handle collapsing and, if the gun is not fired immediately, secures the weapon by moving the safety bolt. The weapon is now cocked, secured and unloaded. After actuating the cover latch, the cover is opened and the cartridge belt is inserted in such a way that the first cartridge rests against the stop on the lower part of the feeder with the bullet forward. The lid is then closed. The weapon is fully loaded and secured. If you only want to leave it partially loaded (higher security), you can insert the cartridge belt so that the first cartridge comes to rest shortly before the cartridge stop. A strong pull on the right end of the belt to the right makes it ready to fire.

The fully charged and secured state means: The closing spring is tensioned. The breech is held in the rear position by the trigger, the trigger is in the front position, the first cartridge is in the feed position, i.e. i.e., it rests against the cartridge stop and is pushed down by the pressure plate in the top of the feeder. The second cartridge is captured by the outer feeder lever. The rear arm of the trigger is blocked by the safety bolt.

After unlocking the MG by moving the safety bolt, the trigger is no longer blocked. By pulling the trigger back past the pressure point, the front arm of the trigger is pushed up by the limiting bolt. The trigger is turned so that its rear arm releases the slide. The release lever engages the trigger and prevents entry into the locking path. This relieves the trigger.

The released bolt snaps forward under the pressure of the relaxing closing spring and pushes a cartridge out of the belt into the chamber of the barrel with its ejector (nose on the bolt head).

As long as the bolt head is in front of the locking piece, the locking rollers rest on the right and left slide rails. When the bolt head enters the locking piece, the locking rollers must follow the locking curves milled into the locking piece. The locking rollers step outwards and finally sit in front of the locking lugs of the locking piece. The wedge-shaped firing pin holder is pushed forward by the bolt housing, pushes the locking rollers completely outwards and blocks them. This largely prevents the lock from rebounding.

Only when the bolt is completely locked and the cartridge has been fully inserted into the chamber does the firing pin in the firing pin holder hit the cartridge's primer. The propellant charge in the cartridge is ignited and the shot is broken. The bullet is driven through the barrel by the high-tension powder gases and is twisted by cutting into the barrel. The bolt remains locked until the bullet leaves the barrel and the gas pressure has dropped to a tolerable level.

Due to its locking and its mass, the breech has a certain persistence with the subsequent run. In addition, the closing spring presses slightly against the lock.

After the bullet emerges from the muzzle, it passes the hole in the recoil nozzle. This is closed for a short time through the bullet passage. This leads to a steep pressure increase in the recoil booster due to the accumulation of powder gases flowing in. The gas pressure that builds up acts on the face of the barrel guide sleeve and pushes it backwards together with the barrel and lock against the recoil spring. The returning barrel guide sleeve finally releases the outflow slots on the recoil amplifier so that the remaining powder gases can escape there.

The gas nozzle with recoil booster acts as a gas cylinder and the pipe guide sleeve as a gas piston . In addition to the recoil impulse, this piston action unlocks the breechblock. First, however, the barrel and breech run back together for about eight millimeters until the locking rollers meet the unlocking cams in the cam piece. The locking rollers are steered inwards and the firing pin holder with firing pin is pushed back. This unlocks the lock as the locking rollers emerge from the locking piece. The breech and barrel separate. The barrel tensions the spring in the vet and is then pushed back into the front end position.

Due to its inertia (mass inertia), the slide retracts further against the pressure of the recoil spring and pulls the empty cartridge case out of the chamber with the extractor. The recoil spring is tensioned until the lock strikes the back of the lock buffer. This absorbs a substantial part of the return energy of the closure.

The locking buffer also pushes the ejector bushing forward, which in turn pushes the ejector in the locking head forward via the ejector rod. This quickly rotates the cartridge case around the extractor and ejects it down through the housing ejection port. The lock then snaps forward again under the pressure of the recoil spring. The process described is repeated until the trigger is released or the belt is empty. When the trigger is released, the advancing bolt swings the release lever forward. The releaser releases the trigger, which jumps into the slide and catches the slide.

Belt feed

The transport bolt runs with its transport roller in the transport lever (U-rail). Since it is firmly connected to the lock housing, it can only move in a straight line. However, the transport lever makes a right-hand bend at the beginning of the last third, which means that the transport roller swivels the transport lever to the left as the shutter moves forward. The transport lever moving to the left pushes the outer feed lever of the belt slider to the right via the connecting lever until the second cartridge is gripped by the inner feed lever (first half-step). When the shutter is reversed, the transport lever swings to the right. As a result, the inner feeder lever also moves to the right until the second cartridge is against the stop on the lower part of the feeder (second half-step). The second cartridge is then pushed out of the belt pocket by the ejector of the leading bolt head. The pressure plate in the upper part of the feeder directs the cartridge downwards so that it is gripped by the push plate and pushed into the cartridge chamber.

## Technical specifications

 Manufacturer Großfuß , MAGET , Mauser Werke , Steyr-Daimler-Puch , Wilhelm-Gustloff-Foundation Number of pieces in World War II 352,000 to 400,000 Weapon system air-cooled recoil charger with a short receding barrel Recoil amplification by muzzle gas pressure Closure type Support roller lock Ammunition feed Link belts, two-step feed from the left caliber 7.92 × 57 mm (after World War II change to NATO caliber 7.62 × 51 mm). The barrel had 7.91mm markings versus 7.62mm on today's barrels Twist type constant right twist Number of trains four / six Twist length 210 mm Length of the weapon with shoulder rest 1230 mm Length of the barrel with locking piece 565 mm drawn length 476 mm Sight length 430 mm Visor open sliding visor 200-2000 m 100 m ascending Weight of the weapon with bipod (unloaded) 11.5 kg Weight of the weapon without bipod (unloaded) 10.6 kg Weight of the barrel with locking piece 1.8 kg Ammunition feed Belt drum (50 rounds), 50 mm belt (which could be connected to each other), 120 decay belt, two-step feed from the left Initial velocity v 0 of the projectile 820 m / s Muzzle energy E 0 approx. 4000 y Max. medium gas pressure 3300 bar Return travel to unlocking 7 mm Return path 21 mm Combat range Bipod : 800 m Carriage : 3000–3500 m Max. Firing range 4000 m Safety distance in the direction of fire 5000 m lateral safety distance each 1000 m fire rate approx. 1500 rounds / min approx. 25 rounds / s${\ displaystyle \ rightarrow}$ Lifespan of the barrel approx. 3500–4000 shots (approx. 8000 shots with hard chrome-plated barrel)