MG 42

Before World War I Even before World War I, the German military was already looking forward to replacing the heavy machine guns which proved to be such a success in that war. The MG13 was one of the first developments toward a goal of producing a weapon that could perform multiple roles, rather than just one. The MG13 was the result of reengineering the Dreyse Water-cooled machine gun to fit the new requirement. Between 1934 and the adoption of the final MG 34 production version, the Waffenamt (German Army Weapons Agency) realized the MG 34 Einheitsmaschinengewehr was too complex and expensive to mass-produce and started looking for ways to simplify and rationalize the technical concept. Development of the MG 42 '' soldier in 1944 carrying an MG 42 configured as a light support weapon with a folding bipod and 50-round basket drum containing the ammo belt. A draft specification was made and a contest was held for an MG 34 replacement. Three companies were asked in February 1937 to submit designs: Metall und Lackierwarenfabrik Johannes Großfuß AG of Döbeln, Rheinmetall-Borsig AG of Sömmerda, and Stübgen AG of Erfurt. The design and mock-up gun proposals were submitted in October 1937. Großfuß AG's entry proved to be the best design by far, employing a unique recoil-operated roller locking mechanism whereas the two competing entries used a gas-actuated system. It was much simpler to build than other machine guns – it took 75 man hours to complete the new gun as opposed to 150 man hours for the MG 34 (a 50% reduction), of raw materials as opposed to for the MG 34 (a 44% reduction) – and cost 250 RM as opposed to 327 RM (a 24% reduction). The initial trials of the Großfuß functional model presented in April 1938 gave rise to improvement requests by the machine gun contest board. The resulting Großfuß MG 39 prototype gun presented in February 1939 remained similar to the earlier MG 34 overall, a deliberate decision made to maintain familiarity and capability to use the various mounts and other accessories developed for the MG 34 to adapt the gun to different roles. The only major changes from the gunner's perspective were dropping of the saddle-drum-magazine feed option, leaving the weapon to fire belted ammunition, or from a single 50-round drum-shaped Gurttrommel belt container fitted to the gun's receiver, and simplifying the weapon's open sights for aiming purposes. All these changes were intended to increase, maintain, or accommodate the gun's high cyclic rate of fire and dispersion. Although made of relatively inexpensive and simple parts, the prototypes proved to be considerably more rugged and resistant to jamming than the precisely machined and somewhat temperamental MG 34. Further trials resulted in selecting the Großfuß MG 39 prototype gun for final production development. A limited run of about 1,500 of further improved MG 39/41 pre mass-production model guns, was completed in 1941 and by the end of 1941 tested in combat trials. Adoption of the MG 42 In early 1942 the final model of the weapon was officially accepted, and manufacturing of the mass-production model began, as the MG 42, contracts going to Großfuß, Mauser-Werke, Gustloff-Werke, Steyr and others. The MG 42 was first deployed in May 1942 by the Deutsches Afrikakorps (German Africa Corps expeditionary force in Africa) and introduced by mid-1942 on all fronts. 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). Brazilian expeditionary soldiers fighting in Italy used to refer to the MG 42 as Lurdinha; this nickname is due to the fact that the bride of one of the soldiers, named Maria de Lourdes, was a seamstress and the sound of MG 42 was similar to the sound of her sewing machine (Lourdinha is a common nickname in Brazil for women called Maria de Lourdes). == Small arms doctrine ==

The German tactical infantry doctrine of the era based a (10-man Gruppe) squad's firepower on the general-purpose machine gun in the light machine gun role. The advantage of the general-purpose machine gun concept was that it added greatly to the overall volume of fire that could be put out by a squad-sized unit. Operating crews could lay down a barrage of fire, pausing only to reload or to replace the barrel, which could be done in less than 10 seconds. This allowed the MG 42 to tie up larger numbers of enemy troops than was otherwise possible. The Americans and the British trained their troops to take cover from the fire of an MG 42, and assault the position during barrel replacement. The (slower) rapid firing rate used in emergency/final defensive line situations of the MG 42 was up to 500 rounds per minute. Two of the standard issue bolt-action Karabiner 98k rifles in the squad could be replaced with semi-automatic Gewehr 43 rifles and occasionally, StG 44 assault rifles could be used to re-arm the whole squad, besides the machine gun. A full Gruppe (squad) carried 1,800 rounds of ammunition for the machine gun between them. Medium machine gun fire support role In the German heavy machine gun (HMG) platoons, each platoon served four MG 34/MG 42 machine guns, used in the sustained fire mode mounted on tripods. In 1944, this was altered to six machine guns in three sections with two seven-man heavy machine gun squads per section as follows: • Squad leader (NCO); MP40 • Machine gunner (private); MG 34/MG 42 and Walther P38 • Assistant gunner (private); pistol • Three riflemen (privates); rifles • Horse leader for horse, cart and trailer (private); rifle The optimum operating crew of an MG 42 in its medium machine gun role was six men: the squad leader, the machine gunner who carried and fired the gun, the assistant gunner/loader who carried the tripod, and three riflemen who carried 1,800 rounds of ammunition between them, spare barrels, entrenching tools, and other items. To enable the machine gun for its long-range direct fire and indirect fire support roles, optical sights could be added to a Zielfernrohrhalter (optical sight mounting bracket) on the tripod, allowing operating crews to continue using advanced planned and unplanned firing methods developed during World War I, though plunging fire or indirect fire methods were not as commonly used by machine gunners during World War II as they were during World War I. ==Operation==

against aerial invasion One of the Einheitsmaschinengewehr (Universal machine gun) roles was to provide low-level anti-aircraft coverage. A high cyclic rate of fire is advantageous for use against targets that are exposed to a general-purpose machine gun for a limited time span, like aircraft or targets that minimize their exposure time by quickly moving from cover to cover. For targets that can be fired on by a general-purpose machine gun for longer periods than just a few seconds, the cyclic firing rate becomes less important. As a consequence, one of the MG 42's most notable features was its high cyclic rate of fire of about 1,200 to 1,500 rounds per minute, twice the rate of the Vickers and Browning machine guns, which fired at a rate of about 600 rounds per minute. The ear could not easily discern the sound of individual shots being fired, hearing a sound described as like "ripping cloth" or a buzzsaw. The MG 42's high cyclic rate of fire 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 MG 42 to carry extra ammunition, thus providing the MG 42 with a backup source when its main supply was exhausted. Another disadvantage of the MG 42 was that the high cyclic rate of fire led to the barrel overheating quickly during rapid fire. After around 150 rounds of rapid fire, the gun operator would open a side hatch (leading to the barrel) and replace the hot barrel with a new cooler one. Non-observance of this technical limitation renders the barrel prematurely unusable. The machine gun crew member responsible for a hot barrel change was issued protective asbestos mitts to prevent burns to the hands. The German military instructed that sustained fire must be avoided at all costs. They ruled that the results of sustained fire were disappointing and that the expenditure of ammunition involved was "intolerable." In the bipod-mounted light machine gun role, MG 42 users were trained to fire short bursts of 3 to 7 rounds and strive to optimize their aim between bursts fired in succession. According to comparative tests by the US military under battle conditions, 5 to 7 round bursts with 22 bursts in a minute were most effective. For its medium machine gun role, the MG 42 was matched to the newly developed Lafette 42 tripod. In this role, MG 42 users were trained to fire short bursts and bursts of 20 to 50 rounds and strive to optimize their aim between bursts fired in succession. As a consequence of factors like the time spent reloading, aiming, changing hot barrels if necessary to allow for cooling, the MG 42's practical effective rate of fire was 154 rounds per minute, versus 150 rounds per minute for the MG 34. ==Design details==

s next to the main gun The MG 42 is a 7.92×57mm Mauser, air-cooled, belt fed, open bolt, recoil-operated machine gun with a quick change barrel. Its parts are attached to a thick stamped sheet metal housing that functions as the receiver and barrel sleeve. It weighed 11.57 kg in the light machine gun role with the bipod, lighter than the MG 34 and easily portable. The underfolding bipod, the same one used on the MG 34, could be mounted to the front near the muzzle to minimize shot dispersion or the center of the gun near the balance point offering more flexibility depending on how and where it was being used. The shoulder stock is designed to permit gripping with the left hand to hold it secure against the shoulder. The MG 42 incorporated lessons hard-won on the Eastern Front. Both the cocking handle and the catch for the top cover to the working parts were designed so that the gunner could operate them wearing arctic mittens or with a stick or rod. This was vital for winter conditions where contact by bare flesh on cold metal could cause severe injury, such as instant frostbite. The MG 42 also functioned well in other climates; dust and dirt in North Africa and Italy was less likely to jam the MG 42 than the more temperamental MG 34. The MG 42 is capable only of fully automatic fire. Single shots are difficult, even for experienced operators, due to the weapon's high cyclic rate of fire and the ability to fire a short burst of no more than three rounds was usually accepted as the training standard. The weapon features a recoil booster at the muzzle which adds extra rearwards force to augment that caused by recoil, thereby improving functional reliability and rate of fire. Besides amplifying recoil and managing and timing rearwards force exerted by propellant gas generated pressure, the recoil booster assembly ends in a muzzle shroud and also functions as a guide sleeve for the barrel and a muzzle flash arrester. As the barrel of the MG 42 is changed through the side of the barrel shroud, rather than directly from the rear as in the MG 34, this made the MG 42 unsuitable for use as internal secondary or co-axial armament on World War II era German tanks or other armored vehicles, with the exception of the Jagdpanzer IV. Early versions of the Jagdpanzer IV carried two standard (no modification made) MG 42s on both sides of the main gun mantlet/glacis, firing through a firing port which was protected by an armored cover plate; the MG 42s were retracted when not in use. Later version Jagdpanzer IVs carried only one MG 42 as internal secondary armament. The MG 42 belt-feed mechanism inspired the design used in the M60 machine gun. The trigger mechanism of the FN MAG or MAG-58 is a virtual copy of the MG 42's, and the FN MAG's belt-feed mechanism is also very similar. Operating mechanism The roller-locked bolt assembly consists of a bolt head, two rollers, a striker sleeve featuring a wedge-shaped front, bolt body, and a large multi strands around a central coil 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. In the locked position during firing, the rollers rest on parallel surfaces relative to the bore axis on the bolt head ensuring a full lockup. Upon firing, rearward force from the recoil of the cartridge ignition combined with the additional rearward force generated by the muzzle booster start to move the barrel and bolt assembly rearwards for a total distance of . These two parts start the unlocking sequence after the barrel and bolt assembly have moved rearwards when the parts have moved far back enough that the rollers start the rest on angled/oblique surfaces and allow the rollers to move inwards, controlled by the wedge-shaped front of the striker sleeve, back to their previous position, unlocking the bolt head and allowing the bolt assembly to further recoil rearwards, extracting the spent cartridge case and ejecting it downwards through an ejection port normally covered by a spring-loaded dust cover at the bottom of the receiver, just in front of the trigger group. The spring-loaded dust cover automatically opens when the gun is fired, but the user has to close it after firing to prevent dirt entering the receiver through the open port. Simultaneously, the barrel is pushed forward by a recuperator spring to its starting position. The three-wire braided return spring then pushes the bolt assembly forwards again, pushing a new cartridge out of the belt into the breech. The sequence repeats as long as the trigger is depressed. The original MG 42 roller-locked action had an undesirable tendency to exhibit bolt-bounce. It was possible to unintentionally have high pressure gas moving backwards in the MG 42 towards the operator(s) when the action was not fully locked. This causes unacceptable dangerous conditions and out of battery ignitions can result in catastrophic gun failures. Enough guns were damaged and put out of action for repair or lost to warrant finding the cause and a solution. After investigation using high-speed photography, the rollers in the bolt were found to "bounce" back and forth or oscillate up to when lock up is proceeding and then they settle into full lock up. Once the problem was identified, the temporary solution was to design and manufacture extra sturdy ammunition with primers with a slightly slower ignition time which allowed the rollers to settle into lockup and issue that ammunition specifically for MG 42 use. A more practical solution to control the harmonics problem in the roller/wedge system and make the MG 42 less ammunition ignition timing sensitive was needed. The roller-locking system inherent problem was solved after World War II by developing and adding bolt-bounce preventing bolt catches to the action. These can also be retrofitted to MG 42 bolts. The cyclic firing rate of the MG 42 can be altered by installing different bolts and return springs. A heavier bolt uses more recoil energy to overcome inertia, thus slowing the cyclic rate of the machine gun. Heavy bolts also were used along with stiffer return springs. The standard MG 42 bolt weight for a 1,500 rounds per minute cyclic rate of fire is . Sights The open-type iron sighting line has a relatively short radius and consists of a "∧-type" height adjustable front sight on a folding post and a leaf rear sight with an open V-notch sliding on a ramp, graduated from in increments. Feeding The MG 42 could use non-disintegrating metallic-link belts, which have links that wrap around the cartridge case and are linked by a coiling wire on each side. The belts are intended for multiple reuse. As in the MG 34, operation through the feed block is by a feed arm housed in the feed cover. The feeding system was based on the direct push-through of the cartridge out of the belt link into the gun's chamber. Accordingly, the link had to be of the half-open type to enable the motion of the bolt through the link. New in the MG 42 was that two belt feed pawls are linked to the front end of the feed arm by an intermediate link, in such a way that when one pawl is feeding, the other pawl is riding over the next round in the belt. Because of that, feed is performed in two steps, on both the opening and closing movement of the bolt, instead of one step as in the earlier MG 34. This enhances the smoothness of the feeding process by improved ammunition belt retention for more precise indexing with the feedway and reduces mechanical stress put on the feed unit and belt links. According to Infantry Journal in 1947, the operating momentum driven MG 42 feed system will not function reliably under a cyclic firing rate of 850 rounds per minute. During World War II the Gurt 34/41-belt family was introduced. Gurt 34/41 belt links and wire spirals were made of thinner material — the Gurt 34 links were made of and Gurt 34/41 links of thick stamped steel sheet metal — that saved ⅓ of metal and counterintuitively yielded improved performance. Belts were supplied in a fixed length of 50 rounds, but could be linked up to make longer belts for sustained firing. Ammunition boxes contained 250 rounds in five 50-round belts. A 250-round Patronengurt 33 belt was also issued to machine guns installed in fixed emplacements such as bunkers. Patronenkasten 34 and Patronenkasten 41 ammunition boxes could hold up to 300 belted rounds and were used in more static non-highly mobile situations. The Patronenkasten could contain an Einführstück belt starter-segment. The Gurttrommel assault drum was an alternative feed option and designed to be clipped to the left side of the gun. It was not a true magazine but held a coiled 50-round belt and corresponding Einführstück starter-segment preventing it from snagging, twisting and getting stuck during mobile assaults. The Gurttrommel belt container was commonly used until the end of World War II, with the MG 42 and the earlier MG 34. Barrel The long barrel and its prong type barrel extension used for lock up, made up the barrel unit of the MG 42. It could be quickly changed by the machine gun crew and weighed including the locking piece. Later produced barrel bores featured hard-chrome plating to make them more durable. The different versions meant that the service life of an MG 42 barrel varied between 3,500 and 8,000 rounds assuming the barrel was used according to the regulations, which prohibited rapid fire beyond 150 rounds. Excessive overheating caused by rapid firing about 500 rounds through a barrel resulted in unacceptable wear of the bore rendering the barrel useless. The Laufschützer 42 was derived from the Laufschützer 34 that served the same purpose for MG 34 barrel units. Later in the war the universal Laufschützer 43 was introduced that could be used with MG 34 and MG 42 barrel units. Lafette 42 tripod MG 42 mounted on a Lafette 42 tripod with MG Z 40 telescopic sight attached For the medium machine gun role a large tripod, the Lafette 42, was available that included a number of features, such as recoil absorbing buffer springs, a Zielfernrohrhalter (optical sight mounting bracket) for mounting an MG Z 34 or MG Z 40 periscope-type 4× power telescopic sight containing special sighting equipment for indirect fire, or the late World War II MG Z 44, designed for direct fire only. Fitting such an optical sight enabled the machine gun to deliver direct fire out to . An accessory to lengthen these sights' periscope was available to use these sights behind cover. The Lafette could be set up in a prone, kneeling or high position. The Lafette 42 weighed on its own and was a simplified version of the Lafette 34 used for the MG 34, as the MG 42 could be operated more easily from a Lafette and featured no semi-automatic firing mode. The legs could be extended with a Lafetteaufsatzstück to allow it to be used in the low level anti-aircraft role, and when lowered, it could be placed to allow the gun to be fired "remotely" while it swept an arc in front of the mounting with fire. Mounted to the Lafette and aimed through the MG Z 34 or MG Z 40 telescopic sight, the effective range of the MG 42 could be extended out to when fired indirectly. The indirect firing method exploits the s.S. Patrone useful maximum range, that is defined by the maximum range of a small-arms projectile while still maintaining the minimum kinetic energy required to put unprotected personnel out of action, which is generally believed to be 15 kilogram-meters (147 J / 108 ft⋅lbf). The Lafette 42 tripod also had a bolt box to store a (spare) bolt and return spring. Another unique feature of German World War II machine guns was the Tiefenfeuerautomat feature on the Lafette 42 and Lafette 34 tripods. It lengthened the beaten zone by walking the fire in wave-like motions up and down the range in a predefined area. The length of the beaten zone could be set on the Tiefenfeuerautomat. E.g., being unsure whether the real distance was , the gunner could make the mount do an automatic sweep between the elevations for and back. This sweeping of a selected beaten zone continued as long as the gun fired. The Lafette 42 had a Richt- und Überschießtafel (Overhead firing table) riveted to the rear body of the searchfire mechanism from the very start of production until the very end of it. In the later stages of World War II ballistic correction directions were added for overshooting friendly forces with S.m.E. - Spitzgeschoß mit Eisenkern (spitzer with iron core) ammunition of which the external ballistic behaviour started to significantly deviate from upwards compared to the s.S. Patrone (s.S. ball cartridge). A trigger handle, which enabled the operator to fire the gun without affecting the aim, was attached to the Tiefenfeuerautomat searchfire unit. There were numerous other specialist mounts for the MG 42. The Dreibein 34, for example, was a simple high-standing tripod for mounting the gun in anti-aircraft mode. There were also mounts for various vehicles, motorcycle sidecars, and fortress positions. MG 42s were mounted in multiple-gun arrangements, particularly for low level anti-aircraft defence. The butt-stock was produced in various wood and bakelite versions. ==Variants and developments==

Finnish MG 42 Finland acquired five MG 42s in July 1943 for evaluation. Three were tested with front units. Finland decided to produce 4,000 MG 42s modified to fire 7.62×54mmR cartridges but only one modified prototype was ever made. MG 45 In 1944, the material shortages in Nazi Germany led to the development of a newer version, the MG 45 (or MG 42V), which had a different operating mechanism that used roller-delayed blowback as opposed to roller locking. For this reason, the MG 45 is considered a different type of firearm, as the mechanisms of these two guns are different. It used steel of lesser quality, which reduced weight to , while retaining the horizontal cocking handle. First tests were undertaken in June 1944, but development dragged on and eventually only ten were built. The tested MG 45 fired 120,000 rounds in succession at a cyclic rate of fire around 1,350 to 1,800 rounds per minute. The MG 45 had some influence in the post-war development of roller-delayed blowback system, as employed in issued CETME, SIG and Heckler & Koch small arms. T24 machine gun The T24 machine gun was a prototype reverse engineered copy of the German MG 42 general-purpose machine gun developed during World War II as a possible replacement for the M1918 Browning Automatic Rifle and M1919A4 for infantry squads. The T24 was chambered for the .30-06 Springfield cartridge. By February 1943, US ordnance authorities published the first report on the MG 42, following testing of a captured gun. The quick barrel changing and belt feed systems were considered some of the best design features. The US Army wanted to be able to manufacture this general-purpose gun because it was technically advanced and much easier to make than the World War II US light and medium machine guns and it was decided to convert several MG 42s to fire .30-06 Springfield M2 ball ammunition. Saginaw Steering Gear Division of General Motors received a contract to construct two working converted MG 42 prototypes designated as the T24 machine gun. It could also be used on an M2 Tripod. When one of the two T24 machine gun prototypes was fired at Aberdeen Proving Ground, it fired only one shot and failed to eject the cartridge. A second attempt had the same result. The other prototype was plagued with excessive ejection failures and to a lesser extent failures to feed. The average cyclic rate of fire of the tested weapon was 614 rounds per minute. From January to February 1944, testing at Aberdeen Proving Ground were unsatisfactory. Firings were discontinued in February 1944 after 51 malfunctions and firing a total of 1,583 rounds by authorization of Major C. Balleisen, O.C.O. By doing so, the Yugoslavs retained the original weapon's design features, making the M53 a near exact copy of the German MG 42. The only major differences were a slower 950 rounds per minute cyclic rate of fire and no anti-aircraft sight mount. The aiming range of the M53 is , and the terminal range of the bullet is , the same as the MG 42. The MG 42s captured in Yugoslavia at the end of World War II were put into reserve of Yugoslav People's Army as M53/42s. The last military use of M53s in Yugoslavia was in 1999. Some quantities of M53s were exported to Iraq in the 1980s and saw extensive action during both Gulf wars. The M53 was known under the nickname Шарац (Šarac). MG 3 At the end of World War II the original technical drawings and data for the MG 42 were captured by the Soviets. These would eventually find their way to Czechoslovakia and Yugoslavia. This forced Rheinmetall to reverse engineer the MG 42 for the development of the MG 3 (originally the MG 1 launched in 1958), which uses the MG 42 design but was rechambered to 7.62×51mm NATO. It remained a primary general-purpose machine gun of the modern German armed forces () until it was replaced by the Heckler & Koch MG5 during the 2020s. The MG 3 has been used by more than 40 countries around the world, and it remains in widespread service today. The MG 3 and its preceding variants all share a high level of parts interchangeability with the original MG 42. Like the MG 42, the MG 3 cyclic rates of fire can be altered by exchanging the standard weight (about ) bolt used for the standard 1,100–1,300 rounds per minute rate of fire for an extra weight (about ) bolt for a reduced 800–950 rounds per minute rate of fire. Those bolts also are used along with different recoil springs. SIG MG710 The Swiss SIG MG 710-3 general-purpose machine gun was based on the design of the MG 45 using a slight modification of the roller-delayed action and chambered for 7.62×51mm NATO. Its cyclic rate of fire is 900 rounds per minute. The first version looks very much like the MG 42. Influence on other designs The MG 42's belt-feed mechanism was copied and used in the design of the M60 machine gun. The trigger mechanism of the FN MAG or MAG-58 is a virtual copy of the MG 42's and its belt-feed is also very similar. ==Users==

, in Zaire, 1973, along with a Madsen machine gun and several Karabiner 98ks and P1914s. • : Used by the National Liberation Front. • : Used by Mukti Bahini forces during the Bangladesh Liberation War • : Supplied from Soviet Union, used by Chinese Militia during the Sino-Vietnamese War. • : Used the M53 model. • : Ex-Portuguese m/944 used by FALINTIL during East Timorese civil war and Indonesian invasion of East Timor. • : Used for evaluation only • • • • : Received 440 units from Germany in 1943. • • : Used ex-German MG 42's. Two of an intended batch of ten MG 42s were converted in Norway to .30-06 Springfield and designated as MG42F1. The conversion project abruptly ended as most of Norway's stockpile of MG 42s was sold abroad at the same time. • : Known as m/944 and was later replaced by the FN Minimi Mk3. • : Used the M53 model. • • : Used during the Bizerte crisis • : Battlefield capture • • : Produced as M53. ==See also==