MG 42

Prior to World War I

Even prior to World War I the German army 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. The Gast gun was developed with the goal of providing a high rate of fire weapon for anti-aircraft use which was reported to have reached rates of fire as high as 1600 rpm.

The concept eventually led to the development of the MG34 which was envisaged and well developed to provide anti-aircraft coverage, highly portable infantry coverage, and even sniping ability. The MG34 was developed to use the standard German rifle round of 7.92 x 57mm Mauser.

The MG 34 was issued with 6 additional interchangeable barrels. The three-man crew that served each weapon was also issued asbestos gloves to use when changing the barrel. As a result, the sustained rate of fire was very high. The MG 34 was so accurate that it was often mounted on a tripod with a telescopic sight for sniping at very long distances. It was chambered in the standard 7.92×57mm Mauser cartridge (often called 8mm).

In German army tactics, the machinegun was supported by the entire squad. Each man would carry belts of 7.92×57mm Mauser for the machine gun. US tactics put the machinegun and its crew largely alone with far less support or emphasis on use. A German squad's purpose was to protect the machine gun, while a US squad's purpose used the machine gun to support the men. In addition to the 6 barrels carried for the MG 34, the squad carried at least 1800 rounds of 7.92×57mm Mauser in belts ready to use.

In 1934, the German Army introduced the MG 34, considered to be the first modern general-purpose machine gun. Equipped with a quick-change barrel and fed either with belts, or from 50-round or 75-round spring-loaded saddle-drum Patronentrommel 34 magazines (with a simple change of feed cover), the MG 34 could sustain fire for much longer periods of time than other portable squad-level weapons such as the American B.A.R. and the British Bren Gun, both of which were fed by box magazines, while also being much lighter and more portable than crew-served weapons like the Browning M1919 or Vickers machine guns (which also lacked quick-change barrels). The MG 34 was also quite versatile; not only was it able to be fed from belted ammunition or a saddle drum magazine, it could also be fired from a bipod, heavy tripods or various pintle mounts for armored vehicles. Switching between a bipod and a tripod required no special tools, as the mounting latch was spring-loaded. Later in the war, the MG 34 was used as the basis for the Luftwaffe's MG 81 flexible defensive gun, and as the MG 34 Panzerlauf, it was used throughout the war as secondary armament on panzers and other vehicles. However, it did have its drawbacks, such as sensitivity to dirt and comparatively expensive production. One attempt at improvement was the MG 34S, an incremental improvement on the basic 34 design.

Development of the MG42

In order to address these issues, a contest was held for a true MG 34 replacement. Three companies were asked to submit designs: Metall und Lackierwarenfabrik Johannes Großfuß AG of Döbeln, Rheinmetall-Borsig of Sömmerda, and Stübgen of Erfurt. Of the number of proposals submitted, Großfuß AG's proved to be the best design by far, employing a unique recoil-operated roller locking mechanism whereas the two competing designs used a gas-actuated system. Interestingly, the company had no earlier experience in weapons manufacture, specializing in pressed and stamped steel components (the company's staple product was sheet metal lanterns). Dr.-Ing. Werner Gruner, one of the leading design engineers with Großfuß, knew nothing about machine guns when he was given the task of being involved with the project, although he specialized in the technology of mass production. Gruner would attend an army machine gunner's course to familiarize himself with the utility and characteristics of such a weapon, also seeking input from soldiers. He then recycled an existing Mauser-developed operating system and incorporated features from his experiences with army machine gunners and lessons learned during the early stages of the war. Being made largely out of stamped metal, the new design required considerably less machining and 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), and cost 250 RM as opposed to 327 RM (a 24% reduction).

The resulting MG 39 remained similar to the earlier MG 34 overall, a deliberate decision made to maintain familiarity. The only major changes from the gunner's perspective were dropping of most of the drum-feed options, leaving the weapon to fire with a loose belt of 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 practical rate of fire. Although made of relatively inexpensive and simple parts, the prototypes also proved to be considerably more rugged and resistant to jamming than the precisely machined and somewhat temperamental MG 34. A limited run of about 1,500 of its immediate predecessor, the MG 39/41, was completed in 1941 and tested in combat trials.

Adoption of the MG42

The weapon was officially accepted, and the main manufacturing of the production design began in 1942, as the MG 42, 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).

Rate of Fire

The maximum cyclic rate of the mechanisms of both the MG34 and MG42 are often exaggerated and inaccurate. Both guns were designed for multiple purposes. The high rate of fire was for anti-aircraft use. The normal rate of fire was far lower than is often stated. The effective rate of fire was much higher than that of the guns used by the Allies, but this was due more to the cooling rate of its six interchangeable barrels, than to the design otherwise. Confusion over this undoubtedly comes from the Gast Gun (1600rpm) and the MG81 aircraft gun (1200rpm). The MG34 and MG42 both were equipped with bolts of different damping rates to control fire rates. In infantry use the rpm was likely to have been lower than 950 rpm.The very light buffer has been reported to have achieved 1200 rpm in these guns, but may in fact reflect confusion over the MG81 and Gast gun rates.

Effective Rates of Fire

Note: The cyclic rate reflects how fast a self-loading firearm can fire, extract, reload, and recock its mechanism to prepare for follow-up shots. This is not, however, the effective rate of fire. The effective rate of fire is the rate at which shots can be accurately (effectively) fired at a specific point target. Many firearms have been developed with high rates of fire which have proven to have extremely low rates of effective fire. An easy example of this is the MAC-10 submachinegun. The MAC-10 in 9mm originally fired at 1200 rpm. At this rate individual shots can no longer be heard so its fire sounds like a giant zipper being ripped apart. When a MAC-10 fires, the probability of hitting a target with more than 1 or 2 rounds is quite low. So it has a very poor effective rate of fire.

The effective rate of fire of the MG34 is listed at 150 rounds per minute while the MG42 achieves a slightly higher 154 rounds per minute. Note that the current MG42, now named MG3 also shows multiple rates of fire with the high rate being 1100-1200 rpm and the low rate being 700-800 rpm on World Guns. No machinegun can fire sustained for very long before melting down. The effective rates of fire of the MG34/42 were higher than allied weapons, but the RPM is not a huge factor in this, the ability to change barrels is. Standard bolt weight is 900 gm. while the light bolt is 650 gm.

For a relevant current example, the US GPMG the M240's cyclic rate is listed as 650 to 950 rpm. But its effective rate of fire is approximately 100 rounds per minute.

Service history

One of the weapon's most notable features was in its exceptionally high rate of fire of about 1,200 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, instead hearing a sound described as like "ripping cloth" or a buzzsaw, giving rise to the nickname "Hitler's buzzsaw" (and the German soldiers' Hitlersäge ("Hitler's saw" or "buzzsaw"). This gun (like the MG 34) was sometimes called "Spandau" by British troops, a traditional generic term for all German machine guns, left over from the famous Allied nickname for the MG 08 Maxim-derivative used by German forces during World War I and derived from its manufacturer's plates noting the city where some were produced.

The method of barrel change made the MG 42 unsuitable for secondary or co-axial armament on World War II era German tanks 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 gun mantlet/glacis, firing through a ball slot which was protected by an armored cover (with the MG 42 retracted) when not in use. Later version Jagdpanzer IVs carried only one MG 42 on the left side.

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:

The MG 42's effect was so devastating that Allied troops were trained before the D Day landings to distinguish its unique sound when fired, which was like cloth being ripped or the sound of a buzzsaw. Allied troops were trained to charge an MG-42-equipped pill box only at the time of its one weakness, which was when its overheating barrel needed to be changed.

German small arms doctrine

While the Americans had standardized a semi-automatic rifle in 1936 (the M1 Garand), the German military kept issuing Karabiner 98k bolt-action rifles due to their tactical doctrine of basing a squad's firepower on the general-purpose machine gun in the light machine gun role so that the role of the rifleman was largely to carry ammunition and provide covering fire for the machine gunners. The German military did experiment with semi-automatic rifles throughout World War 2 and fielded the Gewehr 41 series of which less than 150,000 were built, the Gewehr 43/Karabiner 43 series of which 402,713 where built, and introduced the first assault rifle in 1943 – the MP43 / MP44 / StG 44 series, of which 425,977 were built. Due to the relatively limited production of semi-automatic and assault rifles, the Karabiner 98k of which over 14,600,000 were built remained the primary service weapon until the last days of World War II, and was manufactured until the surrender in May 1945.

Operation

The MG 42 weighed 11.6 kg in the light role with the bipod, lighter than the MG 34 and easily portable. The bipod, the same one used on the MG 34, 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.

The optimum operating crew of an MG 42 for sustained fire operation was six men: the gun commander, the No.1 who carried and 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).

The Allied army doctrines of the era centered on the rifleman, with the machine gun serving a support role, and they utilised weapons with rates of fire of typically 450–600 rpm. The Allied nations had machine guns with similar rates of fire, but mounted them almost exclusively in aircraft, where the fleeting opportunities for firing made such high rates necessary. The only similar Allied weapon was the Vickers K aircraft gun, and that was used by ground forces only in specialized circumstances. German doctrine was the reverse, with the machine gun placed in a central role and rifleman employed in support. This meant that German forces deployed far more machine guns per equivalent-sized unit than the Allies, and that Allied troops assaulting a German position almost invariably faced the firepower of the MG 42. 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 MG 42 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 MG 42, and assault the position during the small window of barrel replacement, which took around 5 to 7 seconds (estimated). The high rate of fire of the MG 42 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.

One of the disadvantages to using the MG 42 was that the high rate of fire lead to the barrel overheating frequently. After around 150 rounds of continuous fire, the gun operator would open a side hatch (leading to the barrel) and replace the overheated barrel with a new one. The machine gun crew member responsible for a hot barrel change was issued protective asbestos gloves to prevent getting burned.

Design details

The MG 42 is 7.92×57mm Mauser, air-cooled, belt fed, open bolt, recoil-operated machine gun with a quick change barrel.

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 down. 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 MG 42 is only capable of fully automatic fire. Single shots are difficult, even for experienced operators, due to the weapon's rate of fire. The usual training objective is to be able to fire a burst of no more than 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 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.

The sighting line consists of a ∧-type post or an inverted "V" height adjustable front sight on a folding post and a leaf rear sight with an open V notch sliding on a ramp, graduated from 200 to 2,000 meters (219 to 2,187 yards). There is an antiaircraft rear peep sight hinged on the open rear sight base. An auxiliary anti-aircraft ring sight is kept in the maintenance kit, and fitting on the barrel jacket to be used in conjunction with the folding antiaircraft rear peep sight attached to the rear sight base.

The barrel of the MG 42 could be quickly changed by the machine gun crew and weighed 1.8 kg (4.0 lb). The barrels could have traditional rifling or polygonal rifling. Polygonal rifling was an outgrowth of a cold-hammer forging process developed by German engineers prior to World War II. The process addressed the need to produce more durable machine gun barrels in less time than those produced with traditional methods. Some barrel bores featured hard-chrome plating to make them more durable. The different versions made that the service life of an MG 42 barrel varied between 3,500 and 8,000 rounds.

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 artic 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.

Lafette 42 tripod

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, MG Z 34 or MG Z 40 periscope-type telescopic sight containing special sighting equipment for indirect fire, or the late World War II MG Z 44, designed for direct fire only. An accessory to lengthen these sights' periscope was available to use these sights behind cover. It could be set up in a prone, kneeling or high position. The Lafette 42 weighed 20.5 kg (45.2 lb) 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 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 telescopic sight, the effective range of the MG 42 could be extended out to 3,500 m (3,828 yd) when fired indirectly.

Another unique feature of German World War II machine guns was the Tiefenfeuerautomat feature on the Lafette 42 tripod. If selected, this feature mechanically controlled the rise and fall of the gun, elevating the gun for five rounds and then depressing it for four rounds. 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. For example, being unsure whether the real distance was 2,000 or 2,300 m (2,187 or 2,515 yd), the gunner could make the mount do an automatic sweep between the elevations for 1,900 to 2,400 m (2,078 to 2,625 yd) and back. This sweeping of a selected beaten zone continued as long as the gun fired.

MG 45

In 1944, the material shortages of the Third Reich led to the development of a newer version, the MG 45 (or MG 42V), which had a different operation mechanism that used 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 9 kg, 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 45/42V fired 120,000 rounds in succession at a rate of fire around 1,350 rounds per minute.

The MG 42V had some influence in the post-war development of roller-delayed blowback system, as employed in modern Heckler & Koch small arms. The SIG MG 710-3 machinegun was based on the design of the MG45 using a slight modification of the roller delayed action. Its rate of fire is stated to be 900 rounds per minute (the same as the heavy bolt MG42) and definitely feasible, unlike the claim above, which is not credible, of a sustained 1350 rpm. This is a cyclic rate, not an effective rate of fire. The effective rate of fire is determined by cooling, not action speed.

T24 machine gun

The American military copied the MG 42 during the war as a possible replacement for the Browning Automatic Rifle and M1919A4 for infantry squads, the new version being chambered in the .30-06 cartridge. Saginaw Steering Gear constructed a working prototype designated as the T24 machine gun. It could also be used on an M2 Tripod. The gun was made as an exact copy of the MG 42 which was chambered in 7.92 x 57mm Mauser Caliber. The only change was to use a barrel chambered in .30-06. The 7.92 x 57 was 300 foot pounds more powerful with a larger bullet, so the suggestion that Saginaw Steering gear abandoned the project because .30-06 is more powerful is untrue. The 7.92 x 57mm is ballistically superior.

When the prototype 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 engineers had made no adjustment to the design to accommodate the longer .30-06 cartridge. The US Army wanted to be able to manufacture this gun because it was so much cheaper to make than current guns. However this never took place. German weapons designers adopted a philosophy during World War II of making guns which could be more efficiently manufactured. The MG 42 was a prime example.

When US soldiers first saw the gun it was ridiculed for its use of stamped steel parts, until it was realized how much quicker and more cheaply guns of this type could be manufactured.

M53

In Yugoslavia this MG 42 variant was built at the state-owned Zavodi Crvena Zastava company as the M53 machine gun using original German machinery, retaining the 7.92×57mm Mauser caliber. 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 are a slower rate of fire and no anti-aircraft sight mount. The aiming range of the M53 is 2,000 m (2,187 yd), and the terminal range of the bullet is 5,000 m (5,468 yd), the same as the MG 42. 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. There is evidence that some M53s are still being used by Peshmerga forces in northern Iraq in the ongoing war against ISIS. M53 was known under the nickname Šarac (Шарац).

MG 3

The MG3 (originally the MG1) is the MG42 design rechambered to 7.62 x 51mm NATO caliber. It is the primary general-purpose machine gun of the modern German armed forces (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-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 the MAG-58's belt-feed is also very similar.

The rate of fire of the MG3 is 650 rounds per minute.

resulted in the Beretta MG 42/59—

MG 74

The final variant to date is the MG 74, developed by Austria and since 1974 it is the standard machine gun of the Austrian Armed Forces.

After its founding in 1955, the Austrian army was equipped with old guns temporarily out of U.S. stocks. Starting in 1959 these Browning M1919 were largely replaced by the MG 42 with modified barrel and bolt for the new 7.62mm NATO caliber. But to introduce a modern weapon of its own production the Office of Defence Technology, in cooperation with Steyr Mannlicher and Beretta developed a gun specifically for the Austrian Army. The German MG 42/59 that was introduced in 1959 with the Bundeswehr to replace the U.S. machine guns, served as the basis, which was similar to the Austrian 7.62 mm MG 42. Targets were to reduce, among other things, the rate of fire and weight and have more versatile sights and mount. The development of the weapon was completed in 1974. It replaced from this year the MG 42 as the MG 74 of the Austrian Federal Army.

The modifications to the basic MG 42 design include an extremely heavy bolt (950 grams vs. the 675 gram MG 3 bolt) which reduces the rate of fire to around 850 rounds per minute. Rate of fire can be varied, if necessary, by changing the shutter. 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 MG 42 design. The MG 74 also has a modern polymer stock and handgrips to save weight. Usually colored a dark green, adjustable rear sight (35° horizontal, vertical 15°) and additional anti-aircraft sight can be mounted optional.

Sig MG710

SIG MG 710-3 machinegun was based on the design of the MG42V/MG45 using a slight modification of the roller delayed action and chambered for 7.62 x 51 NATO. Its rate of fire is stated to be 900 rounds per minute. The first version looks very much like the MG42.