MG42

MG42 (Maschinengewehr 42)
Type	Machine gun
Place of origin	Nazi Germany
Service history
In service	1942–1959, variants to present
Wars	World War II
Production history
Designed	1942
Manufacturer	Metall und Lackierwarenfabrik Johannes Großfuß AG
Produced	1942–1945
Number built	approx. 400,000
Variants	MG45/MG42V, MG1, MG2, MG3
Specifications
Weight	11.57 kg (25.5 lb)
Length	1220 mm (48 in.)
Cartridge	7.92x57mm Mauser
Action	Recoil-operated, roller-locked bolt
Rate of fire	1200 rounds/min (varied between 900 and 1,500 rounds/min with different bolts)
Muzzle velocity	755 m/s (2,475 ft/s)
Effective range	1000 m (1,100 yd)
Feed system	50 or 250-round belt

The MG42 (shortened from German: Maschinengewehr 42, or "Machine Gun 42") was a machine gun that was developed for and entered service with Nazi Germany in 1942, during World War II. The 7.92 mm rifle caliber weapon was developed from, and was intended to supplant the MG34 machine gun, though both were manufactured and used until the end of the war.

Overview

The MG42 has one of the highest average rates of fire of any single-barreled light machine gun resulting in a distinct muzzle report. It has a proven record of reliability, durability, simplicity, and ease of operation. The MG42's lineage continued past Nazi Germany's defeat, forming the basis for the nearly identical MG1 (MG 42/59), and subsequently improved into the still very similar MG2, which was in turn followed by the MG3. It also spawned the Swiss SIG 710-3, MG42/59, and a 5.56 mm Spanish CETME Ameli machine gun, and lent many design elements to the American M60. The Ameli and the MG3 were in service with many armies during the Cold War and remain so into the 21st century.

There were other automatic weapon designs with similar firepower at its inception, such as the Hungarian-Gebauer single-barreled tank MG's and the Russian 7.62 mm GShak aircraft gun. However, the MG42's barrel change system allowed for more prolonged firing in comparison to these weapons.

History

Development of the MG42 was by Metall und Lackierwarenfabrik Johannes Großfuß AG, and resulted from further attempts at improving on the MG34, particularly making them easier to mass-manufacture. A limited run of about 1,500 of its immediate predecessor, the MG39/41, was completed in 1941 and tested in combat trials. It was officially accepted, and the main manufacturing of the production design began in 1942; contracts going to Großfuß, Mauser-Werke, Gustloff-Werke, and others. Production during the war amounted to over 400,000 units (17,915 units in 1942, 116,725 in 1943, 211,806 in 1944, and 61,877 in 1945). It could be produced in roughly half the number of man hours of the MG34, using less metal in the process.

One of the weapon's most noted features was its comparatively high rate of fire of about 1,200 rounds per minute, twice the rate of the British Vickers machine gun and American Browning at 600 round/min. At such a high rate the human ear cannot easily discern the sound of individual bullets being fired, and in use the gun makes a sound described as like "ripping cloth" and giving rise to the nickname "Hitler's buzzsaw", or, more coarsely, "Hitler's zipper" (Soviet soldiers called it the "linoleum ripper"). German soldiers called it Hitlersäge ("Hitler's saw") or "Bonesaw". The gun was sometimes called "Spandau" by British troops from the manufacturer's plates noting the district of Berlin where some were produced. Despite its high rate of fire, the Handbook of the German Army (1940) forbade the firing of more than 250 rounds in a single burst and indicated a sustained rate of no more than 300–350 rounds per minute to minimise barrel wear and over-heating.

So distinct and terrifying was the weapon, that the United States Army created training films to aid its soldiers in dealing with the psychological trauma of facing the weapon in battle. The high rate of fire resulted from experiments with preceding weapons, that concluded that since a soldier only has a short period of time to shoot at an enemy, it was imperative to fire the highest number of bullets possible to increase the likelihood of a hit. This principle was also behind the Vickers GO aircraft gun. The disadvantage of this principle is that the weapon consumed exorbitant amounts of ammunition and quickly overheated its barrel, making sustained fire problematic.

In the late 1930s, the MG34 had proved satisfactory. However, it did have its drawbacks, such as sensitivity to dust and comparatively expensive production. One attempt at improvement was the MG34S, an incremental improvement on the basic 34 design. A much bigger improvement came from a design firm, Metall-und-Lackierwarenfabrik Johannes Großfuß AG, experts in pressed and stamped steel parts. Their efforts resulted in a dramatic reduction in complexity — it took 75 man hours to complete the new gun as opposed to 150 man hours for the MG34, and cost 250 RM as opposed to 327 RM.

The resulting MG39 (redesignated MG42 when adopted in 1942) remained largely similar to the earlier MG34, a deliberate decision made in order to maintain familiarity. The only major changes from the gunner's perspective were dropping the drum-feed options, leaving it with a loose belt of ammunition only, simplifying the weapon's open sights for aiming purposes and to further increase the rate of fire. Although made of relatively cheap parts, the prototypes also proved to be considerably more rugged and resistant to jamming than the somewhat temperamental MG34.

The MG42 weighed 11.6 kg in the light role with the bipod, lighter than the MG34 and easily portable. The bipod, the same one used on the MG34, could be mounted to the front or the center of the gun depending on where it was being used. For sustained fire use, it was matched to the newly-developed Lafette 42 tripod, which weighed 20.5 kg on its own. The barrel was lighter than the MG34's and heated more quickly, but could be replaced in seconds by an experienced gunner.

The optimum operating crew of an MG42 for sustained fire operation was six men: the gun commander, the No.1 who fired the gun, the No.2 who carried the tripod, and Nos.3, 4, and 5 who carried ammunition, spare barrels, entrenching tools, and other items. For additional protection the commander, No.1 and No.2 were armed with pistols, while the remaining three carried rifles. This large team was often reduced to just three: the gunner, the loader (also barrel carrier), and the spotter. The gunner of the weapon was preferably a junior non-commissioned officer (or Unteroffizier).

It was possible for operating crews to lay down a non-stop barrage of fire, ceasing only when the barrel had to be replaced. This allowed the MG42 to tie up significantly larger numbers of enemy troops. Both the Americans and the British trained their troops to take cover from the fire of an MG42, and assault the position during the small window of barrel replacement. The high rate of fire of the MG42 sometimes proved a liability, mainly in that, while the weapon could be used to devastating effect, it could quickly exhaust its ammunition supply. For this reason, it was not uncommon for all soldiers operating near an MG42 to carry extra ammunition, thus providing the MG42 with a backup source when its main supply was exhausted.

Operation

The MG42 is roller-locked and recoil-operated (short recoil) with gas assist. The roller-locked bolt assembly consists of a bolt head, two rollers, a striker sleeve, bolt body, and a large return spring, which is responsible for pushing the bolt assembly into battery (the locked position) and returning it there when it is unlocked and pushed backwards by the recoil of firing or by the charging handle. As the striker sleeve is movable back and forth within the bolt assembly, the return spring is also responsible for pushing the striker sleeve forward during locking (described below). The bolt assembly locks with the barrel's breech (the end the cartridge is loaded into) via a prong type barrel extension behind the breech. As it is recoil-operated and fired from an open bolt, the weapon must be manually charged with the side-mounted charging handle.

The roller-locked recoil operation functions as follows: two cylindrical rollers, positioned in tracks on the bolt head, are pushed outwards into matching tracks in the barrel extension by the striker sleeve and lock the bolt in place against the breech. Upon firing, rearward force from the recoil of the cartridge ignition pushes the striker assembly back and allows the rollers to move inwards, back to their previous position, unlocking the bolt head and allowing the bolt assembly to recoil, extracting the spent cartridge and ejecting it. The return spring then pushes the bolt assembly forwards again, pushing a new cartridge out of the belt into the breech, and the sequence repeats as long as the trigger is depressed. The MG42 is only capable of fully automatic fire. Single shots are exceptionally difficult, even for experienced operators, due to the weapon's rate of fire. Usual training aim is to be able to fire a minimum of three rounds. The weapon features a recoil booster at the muzzle to increase rearwards force due to recoil, therefore improving functional reliability and rate of fire.

The MG42 fires from an open bolt, meaning the bolt (not the firing pin) is held in a rearward position when the trigger is not depressed. Depressing the trigger releases the bolt assembly, of which the firing pin is a component.

The shoulder stock is designed to permit gripping with the left hand to hold it secure against the shoulder. Considerable recoil otherwise causes the stock to creep from its intended position. If the weapon is not properly "seated" on the bipod, a prone gunner may be pushed back along the ground from the high recoil of this weapon.

Variants and developments

Various configurations of MG42. The right-most object is a tripod for anti-aircraft use.

In 1944, the acute material shortages of the Third Reich led to a newer version, the MG45 (or MG42V), which had a different operation mechanism used retarded blowback as opposed to roller locking, used steel of lesser quality, reduced weight to only 9 kg, retaining the horizontal cocking handle. First tests were undertaken in June 1944, but development dragged on and eventually only ten were ever built. The tested Mg45/42V fired 120,000 rounds in succession at a rate of fire around 1,350 rounds per minute. The MG42V had some influence in the post-war development of roller-delayed blowback system, as employed in Heckler & Koch modern small arms. The MG45/MG42V should be considered a different firearm however as the mechanisms of these guns were different from that of the MG42.

The American military tried to copy the MG42 during the war, the new version being adapted for the .30-06 cartridge. Saginaw Steering Gear constructed a working prototype designated as the T24 machine gun. However, a design flaw in the prototype and the realization that the cartridge might be too powerful for the gun's mechanism to easily cope with resulted in the discarding of the project.

The MG42, with small modifications, resulted in the MG42/59 and Rheinmetall MG3, which is the primary general purpose machine gun of the modern German army (Bundeswehr). A number of other armies around the world have adopted versions of the original, especially the MG3, and it remains in widespread service today. Its belt-feeding mechanism was adopted for the design of the M60 machine gun. The T161 beat the FG 42-derived T52 during tests in the 1950s to become the M60. The T161 used a different gas system and was easier to make than the T52, but they both used a similar belt-feed and basic configuration. The trigger mechanism of the FN MAG is a virtual copy of the MG42's and the belt feed is also similar.

The final variant to date is the MG74, developed by Austria. The modifications to the basic MG42/MG3 design include an extremely heavy bolt (much heavier than the 950 gram MG3 bolt) which slows the rate of fire to around 850-900 rounds per minute. In addition, a select fire trigger group was added to allow semi-automatic fire (single shot) compared to the traditional fully automatic only fire capability of the original MG42 design. Manufactured by Steyr the MG74 also has a modern polymer stock and handgrips usually colored a dark green. It is chambered for the NATO 7.62 x51 round.

• Rate of fire: Variable, from 850 rounds/min to 1,600 round/min or more depending on installed bolt weight (different weight bolt components introduced to regulate rate of fire, lighter assemblies providing faster rates of fire). Throat erosion and component wear also introduced significant variation. Up to 1,800 round/min on the MG45 or without "recoil booster" (Rückstoßverstärker).
• Parts changes:
  • Barrel: 3 to 7 seconds
  • Barrel and lock: 25 to 30 seconds

The MG42 was adopted by a number of armed organizations after the war, and was copied or license-built as well. Yugoslavia license-built the MG42 as the M53, retaining the 7.92x57mm caliber. By doing so, the Yugoslavians retained the original weapon's design features, making the M53 a nearly exact copy of the German MG42. The only major difference is a slower rate of fire. The aiming range of the M53 is 2000 meters, and the terminal range of the bullet is 5000 meters, the same as the MG42.