The MG 34 is a German air-cooled machine gun.
Originally based on the Rheinmetall MG 30, the MG 30's design was modified and adapted by Heinrich Vollmer of Mauser Industries. The feed mechanism was modified to fit drum magazines and belts, and the rate of fire was bumped up. A double crescent trigger was fitted so it could fire semi or fully-automatically.
In the field, the MG 34 could take on an offensive or defensive role, where the offensive model uses a mobile soldier with the gun fitted with a 50 round drum magazine, while the defensive model was that the gun was mounted on a bipod or tripod and fed by belt. Belts were carried in boxes of five, each belt containing fifty rounds. Due to the heat generated by its high sustained rate of fire, the barrel would overheat and cause the gun to cook off, so the MG 34 has interchangeable barrels. Changing barrels was a very rapid process, where one swings the gun's receiver to the right after disengaging a latch.
As the mainstay of the German Army, the MG 34 was used until its role was supplanted by the MG 42. While the 34 was reliable and dominant on the field, its dissemination throughout the German forces was hampered due to its precision engineering, resulting in high production costs and slower manufacturing.
The MG 34 fires from an open bolt which helped improved airflow through the barrel, allowing it to cool faster. The MG 34 was designed with a rotating bolt operated by short recoil aided by a muzzle booster. When it is ready to fire, the bolt is pulled to the rear and is held back by the sear, where a cartridge is stripped from the magazine or belt and is pushed into battery. As the bolt moves back forward, it rotates, engaging the locking lugs and chamber locking the bolt to the barrel. As the striker strikes the primer and fires the round, the recoil causes its barrel and bolt to move back a short distance, disengaging the locking lugs on the bolt and causing it to rotate back. After which, the bolt recoils to its rear position while the barrel returns forward, while the empty casing is ejected and the cycle begins anew.
The MG 34 has a double crescent trigger, providing select-fire capabilities without a selector switch.
The MG 34 has a few major variants, for different purposes.
- MG 34/41 (MG 34S)
This was a variant of the original MG 34 which could cope with a higher fire rate. It was requested after first war experiences in the beginning of World War II.
- MG 34 Panzerlauf
The Panzerlauf was used on German tanks as secondary armament. As the MG 42 was ill-suited for coaxial mounting due to the method of barrel change, the MG 34 Panzerlauf was born. The Panzerlauf had a heavier, almost solid armored barrel shroud, almost completely lacking the ventilation holes of the original MG 34. When mounted in a tank, the Panzerlauf lacked a buttstock.
- MG 81
The MG 34 was used as the basis for another machine gun, the MG 81, an aircraft-mounted machine gun. For the role, the breech was modified so that the gun could feed from either side. There was even a version where two of these guns was bolted together on a single trigger to form the MG 81Z (Z for Zwilling, German for "twin" as in twin-mounted). While a huge improvement over guns like the MG 15 and the MG 17 which were based on the MG 30 design, the two former guns were used until the end of the war. As the Luftwaffe lost air superiority, MG 15s and MG 81s were adapted for ground use, with varying degrees of success.