Austro-Hungarian Machine Gun - Schwarzlose

Schwarzlose Heavy Machine Gun Model 07/12
Schwarzlose MachinenGewehr M07/12
Schwarzlose Géppuska M07/12

Made by OEWG Steyr, 1905-18 and FGGY Budapest 1914-18
Caliber: 8x50R
Delayed blowback
1067mm [42"] overall, 20kg [44 lbs] + tripod 19.9kg [43.8 lbs]
527mm [20.75"] barrel
Tangent rear sight 200-2400 schritt (lépés) [150-1800 meters]
Muzzle velocity 2000 feet/sec
Cyclic rate: 400 rpm

This gun is remarkable for being the only machine gun based on the retarded blowback system which met with any degree of success prior to 1950. It was invented by Andreas Wilhelm Schwarzlose in Germany, in 1902. Steyr purchased the manufacturing right in 1905. The Austro-Hungarian Infantry and Cavalry adopted it in 1907, the rest of the armed forces in 1914. This weapon has a fixed barrel, few moving parts and rugged construction. The breech is at no time truly locked. When the gun fires, the rearward thrust of the exploding gases actually starts the action opening at the same instant it starts the bullet down the barrel. However by using a very short barrel and a combination of very heavy recoil parts and springs, plus a system for developing a mechanical advantage in the mechanism, Schwarzlose produced a machine gun which permitted the use of military rifle cartridges without an impossibly heavy breech mechanism.
The gun barrel was water cooled. Its cooling jacked held 3 liters of water. An oiling system was used to facilitate the extraction of the fired cases. According to an Austrian source, the lubrication of cartridge cases prevented case ruptures caused by the action opening so fast that it drew the case back while the bore pressure was still too great, and the case was still sealed by expansion to the barrel chamber wall. An oil pump was built in, and on each stroke oil was squirted into the chamber to lubricate the incoming cartridge case. The capacity of the oil contaner was .5 liter, sufficient for 4500 rounds. The empty shells were ejected to the left.

In 1914 after the start of WW1 the Monarchy sequestered 6.5x54mm Schwarzlose machine guns intended for Greece by Steyr. These were utilized on the Eastern Front on Reconnaisance air planes. The pilots carried Mauser C-96 pistols with buttstocks or Mannlicher M.95 carbines for protection on the ground in enemy territory.

Schwarzlose M.07/12 Machine Gun Details

Photos courtesy of Gabor Schneider

Schwarzlose M.07/12 Machine Gun 8x50r Cartridges

Standard Infantry Cartridge 93.M
The 93.M 8x50mm Austro-Hungarian cartridge was used for the M.95 Mannlicher infantry weapons. It has a rimmed brass shell, containing 67% copper and 33% Zinc. The bullet is round nosed steel jacketed lead. This cartridge was used in the Schwarzlose until 1915, when they switched using the 93.M MF.

93.M 8x50mm MF Cartridge (Flieger Munition)
This cartridge was manufactured by Wöllersdorf Ammunition Factory for Austro-Hungarian Machine Gun use from 1915-18. It is similar to the standard infantry cartridge, but the bullet is held by a circular indentation of the case neck, and the primer is held by 3 crimpings. This strengthening allowed problem free faster handling of the ammunition in the machine guns.

Special Cartridges
Originally designed by Alder Company in Oberlaa, Austria. for the Monarchy. Usually the special ammunition was used together with the 93.M MF cartridges as every fifth round in the machine gun belt. The Schwarzlose machine gun's 250-round belt contained 200 MF cartridges and 50 special cartridges.

FZ Nyomjelzős töltény (FZ = Flugbahnzeigend Patrone) [Tracer cartridge]
Major parts: 1. Steel jacket. 2. Lead core. 3. Charge chamber. 4. Lead core. 5. Tracer charge. 6. Delay powder. 7. Cover plate.
Function: After leaving the barrel the black powder is activated, and after delayed for 100m distance, it fires the tracer charge, which leaves a well visible white line from 100-700 meters. Accuracy was not as good as the 93.M MF cartridge's. In 1918 the SP cartridge replaced the FZ cartridge.

Időzített robbanó töltény (LE = Lufteinschiess Patrone) [Timed explosive bullet]
Major parts: 1. Steel jacket with hole at the point. 2. Lead core. 3. Lead jacket. 4. Explosive charge. 5. Delaying black powder. 6. Firing pin. 7. Firing pin spring. 8. Primer.
Function: While the bullet still rotating in the barrel, the spring and firing pin fires the primer. The delaying powder burns until the bullet travels 300-325m and then explodes the bullet. The explosion will result in a white smoke cloud. This cartridge was used until the end of 1917.

Gyújtó-robbanó töltény (B = Brandgeschoss Patrone) [Incendiary Explosive bullet]
Major parts: 1. Steel jacket. 2. Lead core. 3. Rear lead core. 4. Lead jacket. 5. Explosive charge with sleeve. 6. Primer. 7. Firing pin sleeve. 8. Pin ring. 9. Firing Pin.
Function: While the bullet still rotating in the barrel, the firing pin and pin ring moves into the rear position. When the bullet hits, the firing pin moves forward, hitting the primer firing the small .9g explosive charge. A small white smoke cloud indicated the hit. This cartridge was in use 1915-17 when the P cartridge replaced it.

Robbanó-gyújtó töltény (BP = Ballon Phosphor Patrone) [Explosive bullet]
Major parts: 1. Steel jacket. 2. Lead cover. 3. Lead core. 4. Steel jacket. 5. Holding sleeve with .5g yellow phosphorus. 6. Primer. 7. Dual spiral spring. 8. Firing pin with head. 9. Cover. 10. Two half ring spacers.
Function: The centrifugal force of spinning forces the cover back to open holes where the half ring spacers can fly out, also from centrifugal forces. When the bullet hits, the firing pin initiates the explosion. Combination of the B and P cartridges. Purpose was blowing up gas tanks, air balloons. It was a complicated mechanism with 22 parts. This cartridge was used until the end of 1917, when manufacturing was discontinued due to the complexity of the design and the high expense of manufacturing.

Nyomjelző-gyújtó töltény (P = Phosphor Patrone) [Tracer bullet]
Major parts: 1. Steel jacket. 2. Upper lead core. 3. Lower lead core. 4. Holding sleeve with .9g yellow phosphorus. 5. Copper plate. 6. Discharge opening.
Function: The heat from the friction between the bullet and the barrel melts the discharge opening plug. Due to centrifugal forces the Phosphorus leaves through the opening and ignites contacting the air, leaving a smoke line up to a 400m distance. A rounded bullet. It replaced the FZ bullet in 1917 because the FZ's unreliability. It was replaced with the improved SP17 cartridge at the end of 1917.

Hegyes nyomjelző-gyújtó töltény (SP 17 Phosphor Patrone) [Pointed Tracer bullet]
Major parts: 1. Steel jacket. 2. Upper lead core. 3. Lower lead core. 4. Holding sleeve with .9g yellow phosphorus. 5. Copper plate with one hole. 6. Discharge opening.
Function: was same as the P cartridge. The bullet was pointed and the design was simplified. The ballistics were improved and it functioned more reliably than the P cartridge. Used from the end of 1917.

Hegyes nyomjelző-gyújtó töltény (SP 18 Phosphor Patrone) [Pointed Tracer bullet]
Major parts: 1. Steel jacket. 2. Holding sleeve with 1g yellow phosphorus. 3. Lower lead core. 4. Copper plate with two holes. 6. Discharge opening. Function: was same as the P cartridge. The most improved Phosphorus tracer cartridge with excellent ballistics, improved accuracy and tracing distance. Used only on the Italian front in the 2nd half of 1918.

8x50 Cartridge data:

                         MF     FZ     LE     B      P      BP    SP17   SP18
Cartridge weight (g)    28.35  28.95  27.0   23.6   29.6   24.9   23.6   23.6
Bullet weight (g)       15.8   16.35  14.5   11     17     12.3   11     11
Shell weight (g)         9.8    9.8    9.8    9.8    9.8    9.8    9.8    9.8
Powder weight (g)        2.75   2.6    2.7    2.8    2.8    2.8    2.8    2.8
Cartridge length (mm)   76     76     76     76     76     76     76     76
Shell length (mm)       50.2   50.2   50.2   50.2   50.2   50.2   50.2   50.2
Bullet length (mm)      31.8   38.4   40     36     38     38     34.5   35.1
Muzzle velocity (m/s)   580    580    600    700    700    700    800    800
Primer coloring          -     Red     -     Black  Blue   Black  Black  Black

Austro-Hungarian Ammunition manufacturing factories:

Weiss Manfréd Rt., Csepel, Hungary
Roth Testvérek, Pozsony, Hungary
Wöllersdorf Ammunition Factory, Austria
Roth Brothers, Vienna, Austria
Alder Factory, Oberlaa, Vienna, Austria

Schwarzlose Heavy Machine Gun Model 07/31
Schwarzlose Géppuska 07/31.M

The Schwarzlose 07/12.M remained in active Hungarian service after WW1. Starting in 1931 some Schwarzlose machine guns were modified to use the 8x56mm 31.M 'Hegyes' cartridge, these are called the Model 07/31.M. The chambers were re-bored for the new cartridge and new metric rear sights were installed. Muzzle velocity increased from 580m/s to 700 m/s. The new pointed (cone shaped) bullet was not held by the chamber as well as the old cylindrical round-nosed bullet. During firing the pointed bullet had to travel a few mm without proper guidance and seal by the chamber/barrel area. This caused pressure loss and functional problems. To eliminate this problem, this area of the barrel was cold pressed to achieve a smaller interior diameter before the chamber was bored. This method increased the muzzle velocity to 730m/s and provided better reliability.
The gun was fed by a canvas belt, during WW2 metal belts were also used.

632 Madsen light machine guns were purchased from Denmark in 1914.
Bergmann light machine gun was being used for air defense.
After WW1 the Hungarian Gebauer Machine Guns were developed for Plane/Tank/Boat use.