Schwarzlose Machine Gun

Origins

By 1900 the recoil-operated Maxim Gun had shown what a belt-fed machine gun could do, and every major army wanted one. The Maxim was costly to make, however, and its maker held strong patents. Andreas Wilhelm Schwarzlose, a German gun designer who had already produced pistols, looked for a simpler way to build an automatic weapon. Around 1902 to 1905 he patented a machine gun that worked without locking the breech at all. Austria-Hungary tested it against rival designs and adopted it in 1907 as the M.07. The gun was made by the state arms works at Steyr, the maker of the army's Steyr-Mannlicher M1895 rifle, and fired the same 8 mm rimmed cartridge. An improved model with a stronger action and other changes followed in 1912 as the M.07/12, which became the main version.

Design & Construction

The Schwarzlose was a delayed-blowback weapon. When a round was fired, the gas pressure pushed the cartridge case back against the bolt. The bolt was not locked, but it was heavy, it was held by a strong spring, and it was joined to the receiver by a toggle joint that worked at a mechanical disadvantage when the bolt began to move. Together these slowed the opening of the breech enough for the pressure to fall to a safe level. To make this work with a full-power rifle cartridge the barrel was kept short, about 530 mm, which gave the gun a stubby look and a large muzzle flash. Early guns carried a small oil pump that lubricated each cartridge so the case would extract without tearing. The barrel was water-cooled inside a jacket, ammunition came in 250-round fabric belts, and the gun was fired from a heavy tripod. It had far fewer parts than the Maxim, and soldiers found it easy to strip and maintain. The gun alone weighed about 20 kg, and the tripod about as much again. The rate of fire was roughly 400 to 600 rounds a minute, depending on model and ammunition.

Combat Use

When World War I began in 1914 the Austro-Hungarian army had relatively few machine guns, but production grew steadily through the war. Schwarzlose teams fought in Galicia and the Carpathians against Russia, in Serbia, in Romania and above all on the Italian front, where guns sited in rock and snow along the Isonzo and in the Alps cut down repeated Italian attacks. A lighter M.07/12 without the water jacket and a faster-firing M.16 were fitted to aircraft, though synchronizing the slow-firing gun to fire through a propeller was never fully satisfactory. Italy captured large numbers and used them against their former owners. The Netherlands, which had stayed neutral, built the gun as the M.08 and later models in its 6.5 mm cartridge. Sweden adopted it as the m/1914 in 6.5x55 mm and made it at Carl Gustaf. In German service it was used alongside the Maxim-based MG 08 when supplies ran short.

Legacy

After 1918 the Schwarzlose passed to the successor states of the old empire. Austria and Hungary converted many guns to a more powerful 8x56 mm rimmed cartridge in the 1930s, and Czechoslovakia, Yugoslavia, Poland, Italy and Greece also held stocks. Dutch, Hungarian and Italian guns saw service in World War II, and some remained in reserve stores long afterward. The design was a dead end in one sense, since later machine guns used locked breeches or gas operation, but it proved that an unlocked delayed-blowback action could handle a full rifle cartridge. It stands beside the Maxim and the Vickers Machine Gun as one of the great water-cooled guns of the trench era.