The German MG 42

MG 42 crucial cog in German war machine

Ivo Dimitrov

The MG 42 (Maschinengewehr 42 or ‘Machine Gun 42’) is a general-purpose machine gun designed in Germany, chambered in 7.92x57mm Mauser and used extensively by the German Armed Forces during the second half of World War Two. It entered production in 1942 intending to supplement and replace its predecessor, the MG 34, which was more expensive and took longer to produce. The MG 34 was fully machined whereas the MG 42 used a lot of stamped metal sheet parts, but both remained in production until the end of the conflict. The MG 42 is arguably the most famous machine gun of WWII.

Designed to be low-cost and easy to build, the MG 42 proved a highly reliable option. It’s notable for its high cyclic rate of fire, averaging about 1200 rounds per minute compared to around 850 for the MG 34 and perhaps 450-600 for other common machine guns like the M1919 Browning or Bren. This feature made it effective in providing suppressive fire and its unique sound gave it the nickname ‘Hitler’s buzzsaw’.

The MG 42 was adopted by several armies after the war and was both copied and built under licence. Its lineage continued past Germany’s defeat, forming the basis for the almost identical MG 1 (MG 42/59) chambered in 7.62x51mm NATO (.308 Winchester), which subsequently evolved into the MG1 A3 and later the Bundeswehr’s MG 3, Italian MG 42/59 and Austrian MG 74. It also spawned the Yugoslav unlicensed and near-carbon copy Zastava M53.

The MG 42 lent many design elements to the Swiss MG 51 and SIG MG 710-3, French AA-52, American M60 and Belgian MAG general-purpose machine guns and the Spanish 5.56x45mm NATO Ameli light machine gun, though these feature other operating mechanisms to the MG 42.

Its predecessor the MG 34 was the first general purpose machine gun to be adopted into military service. The concept of the general purpose machine gun was that one system could serve both light and heavy machine gun roles, thus eliminating the need for two separate guns. The MG 34 was a revolutionary concept but was fully machined and therefore comparatively complex, expensive and time-consuming to produce.

In order to address these issues a contest was held for an 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 proposals submitted Großfuß AG’s proved the best design by far, employing a unique recoil-operated roller locking mechanism while the other two designs used gas-operated systems.

The roller-locking bolt contributes to the gun’s quick locking and unlocking of the barrel process and consequently its high rate of fire. The company had no earlier experience in firearms manufacture, specialising in pressed and stamped steel components (their staple product was sheet metal lanterns). Dr Werner Gruner, one of the leading design engineers with Großfuß, knew nothing about machine guns when he became involved in the project but did specialise in the technology of mass production.

Gruner attended an army machine gunner’s course to familiarise himself with the characteristics and also sought 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 from stamped and appropriately hardened metal, the new design required considerably less machining and fewer high grade steel alloys. It was much simpler to build than other machine guns, taking 75 man-hours to complete as opposed to 150 man-hours for the MG 34, and cost 250 RM as opposed to 327 RM (a 24 per cent reduction).

The MG 42 was fed with the same metal belts as the MG 34 and could also attach the same 50-round drum-shaped Gurttrommel belt container, the gun  being air-cooled, recoil operated and open-bolt firing. 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 recoil of the cartridge moves the barrel and bolt assembly rearwards about 8mm. These two parts unlock when the striker assembly moves far enough back and allows the rollers to move inwards to their previous position, unlocking the bolt head and allowing the bolt assembly to further recoil rearwards, extracting the spent cartridge and ejecting it down. Simultaneously the barrel is pushed forward by a recuperator spring to its original position, the recoil spring then pushing the bolt assembly forward again, thrusting a new cartridge out of the belt into the breech. This sequence repeats as long as the trigger is depressed.

Due to its high rate of fire the original MG 42 roller-locked action had an undesirable tendency to exhibit bolt-bounce which causes unacceptable dangerous conditions on firing and upon investigation, the rollers in the bolt were found to ‘bounce’ back and forth as the bolt locked. The roller-locking system’s inherent problem was solved by developing and adding an anti-bolt bounce spring buffer inside the bolt. The cyclic firing rate of the MG 42 can be altered by installing different bolts and recoil springs – a heavier bolt uses more recoil energy to overcome inertia so slows the cyclic rate of the gun.

Another unique feature of the MG 42 is the quick change of barrel, which can be accomplished in seconds by simply opening the barrel release latch to the right and pulling the barrel out, this being necessary as barrels were prone to overheating due to the high rate of fire. The second gunner carried spare barrels and asbestos gloves for a quick change.

The gun, like its predecessor, could be fired in the light MG role on a bipod or mounted on a lafette tripod in the heavy role. The MG 42 lafette featured the same sophisticated characteristics of the MG 34 lafette, indirect and direct line of fire adjustable optics and recoil operated mechanism which could sweep a predetermined area with fire in a wave-like motion.

The MG 42 (like the 34) was sometimes called ‘Spandau’ by British troops, a traditional generic term for all German machine guns left over from the Allied nickname for the MG 08 Maxim derivative used by German forces during World War One, originating from its manufacturer’s plates noting the Arsenal of Spandau in the suburb of Berlin where some were made.

Production began in 1942 and contracts went to Großfuß Maget, Mauser-Werke Borsigwalde, Gustloff-Werke and Steyr, assembly during the war amounting to more than 400,000 units (17,915 units in 1942, 116,725 in ’43, 211,806 in ’44 and 61,877 in ’45). In order to disguise the origin of manufacturer each one was assigned a three-letter code (in the case of Mauser a two-letter code: ar). MG 42s made in 1942 were dated with the year and from 1943-45 the date was also disguised with a two-letter code. In 1945 the manufacturers’ three-letter codes were also altered.

The following maker/year codes can be found at the rear end of MG 42 receivers: Maget: cra GH (1943), cra NC (’44), cra NC (’45) serial numbers from 1211 up. Gustloff Werke: dfb FG (1943), dfb mu (’44), svq sm (’45). Mauser-Werke Borsigwalde: ar jt (1943), ar df (’44), dd df (’45). Steyr: bnz Gz (1943), bnz pj (’44), swj PJ (late ’44), swj xe (’45).

The example shown here was made by Maget (Maschinenbau und Gerätebau-Berlin) (cra) in 1944 (NC) and was refurbished and used post-war as seen by the force matched electro pencilled serial number on the top cover.

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