[9] The versatile MG 34 was chambered for the fully-powered 7.92×57mm Mauser rifle cartridge and was arguably the most advanced machine gun in the world at the time of its deployment.

[10] The MG 34 was envisaged and well-developed to provide portable light and medium machine gun infantry cover, anti-aircraft coverage, and even sniping ability.

Its combination of exceptional mobility – being light enough to be carried by one man – and high rate of fire (of up to 900 rounds per minute) was unmatched.

[11] The Einheitsmaschinengewehr concept required that the operator could radically transform the machine gun for several purposes by changing its mount, sights and feed mechanism.

The Swiss and Austrian militaries had both licensed and produced the MG 30 from Rheinmetall shortly after it was patented and the gun started to enter service in Switzerland.

Vollmer originally designed the feed mechanism to accept MG 13/MG 15 inspired 75-round Patronentrommel 34 spring-loaded saddle-drum magazines.

The Patronentrommel 34 was a rather complex magazine for which a filling device had to be used and requiring ordnance personnel and a special tool to optimize the spring tension for reliable feeding.

[12] The result, the multiple role capable MG 34, wherein Rheinmetall's Sömmerda plant had a significant influence, reflected the Reichswehrministerium specifications.

Before large scale production commenced, 2,300 MG 34s in two main early versions, slightly more complex and different from the final design, were produced between 1935 and 1939.

[15] During the period between 1934 and the adoption of the final version the Waffenamt 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.

[17] For its successor, the faster firing, less complex, sensitive and cheaper MG 42, the Germans instead used mass production techniques similar to those that created the MP 40 submachine gun.

In a stationary defensive role, the gun was mounted on a bipod or tripod and fed by a non-disintegrating metal ammunition belt.

[23] Some models captured from the Germans by the Soviets or manufactured in Czechoslovakia post-WWII were supplied to the People's Liberation Army/People's Volunteer Army,[22] PAVN and the Viet Cong during the Cold War.

[24] Several hundred more MG 34s that were in use with these groups were taken from either French or other Western nations fielding captured German weapons fighting against them in colonial wars or anti-communist conflicts.

[25] 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.

The Americans and the British trained their troops to take cover from the fire of an MG 34, and assault the position during the small time window of barrel replacement.

[4] As a consequence of factors like the time spent reloading, aiming, changing hot barrels if necessary to allow for cooling, the MG 34's practical effective rate of fire was 150 rounds per minute.

[4][29] The Allied nations' infantry doctrines of World War II based a squad's/rifle section's firepower centered on the rifleman and/or a magazine fed light machine gun (BAR, Bren, DP-27/DPM, FM 24/29), and they utilised weapons with cyclic fire rates of typically 450–600 rounds per minute.

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.

[47] The barrel of the MG 34 could be quickly changed to avoid overheating during sustained fire by the machine gun crew and weighed 2 kg (4.4 lb).

The entire receiver section could then pivot off to the right on its latitudinal axis, allowing the operator to pull the (hot) barrel out the back of the sleeve.

The machine gun crew member responsible for a hot barrel change was issued protective asbestos mitts to prevent burns to the hands.

Trigger groups on examples used on the eastern front used aluminium grip panels as bakelite tended to crack in the cold.

The Lafette 34 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.

– Spitzgeschoß mit Eisenkern (spitzer with iron core) ammunition of which the external ballistic behaviour started to significantly deviate from 1,500 m (1,640 yd) upwards compared to the s.S. Patrone (s.S. ball cartridge).

The prototype weapons were developed into the very similar further improved MG 34/41, that could cope with a cyclic firing rate of 1,200 rounds per minute, but its components became highly stressed.

Technically, the ejector assembly was enlarged and strengthened, and the feed mechanism was modified to provide a more secure grip on the cartridge.

[citation needed] A limited run of MG 34/41 model guns, was completed and tested in combat trials at the Russian front.

[59] A kit for quick conversion to ground use in the light machine gun role was carried inside the tank containing a butt-stock and a combined bipod and front sight assembly.

For this role, the breech was slightly modified to allow feeds from either side, and in one version, two guns were bolted together on a single trigger to form a weapon known as the MG 81Z (for Zwilling, German for "twin" as in twin-mounted).