I'm so sorry I forgot to mention this.
During the first two years of aerial warfare, especially in conflicts like World War II, heavy machine guns were mainly used as defense against low-flying enemy aircraft. These weapons, usually between 12.7 mm and 20 mm in caliber, were mounted on fixed positions or mobile platforms and aimed to deter or shoot down planes attacking strategic targets, such as cities, factories, or military convoys.
Their effectiveness relied on fire density and coordination between multiple guns: a single gun had a low chance of hitting an aircraft, but several guns firing together could create a “curtain of bullets” that made attacks much more difficult. However, they were less effective against high-altitude bombers because their maximum range was limited and accurate targeting was challenging without specialized tracking systems.
In short, heavy machine guns served as a first line of anti-aircraft defense, particularly against low-level attacks, providing immediate protection to troops and installations before larger guns or dedicated anti-aircraft artillery could engage.
Lewis automatic machine gun
Maschinengewehr 08
Mitrailleuse Automatique Hotchkiss modèle 1914
