<P> In 1903, French military theorists noticed that the machine guns of the day, heavy and relatively immobile, were of little use in infantry assaults . They determined that "the machine gun must learn to walk". They researched the possibility of a light machine gun which could be carried by troops . A marching fire tactic was theorised, using incidental suppressive fire, with the advancing troops considered a deadlier threat than the un-aimed bullets, causing the enemy to fall back . The prototype guns were not approved for production, and none were in service when the war began . At the start of hostilities, France quickly turned an existing prototype (the "CS" for Chauchat and Sutter) into the lightweight Chauchat M1915 automatic rifle with a high rate of fire . The French Army was equipped with it, and the first American units to arrive in France used it in 1917 and 1918 . Hastily mass - manufactured under desperate wartime pressures, the weapon was prone to jamming and overheating . Seeing the potential of such a gun, the British Army settled upon the American - designed Lewis gun fitted for a . 303 - inch (7.7 mm) round; infantry platoons provided with the guns were instructed in fire and movement tactics . The Lewis gun was the first true light machine gun that could in theory be operated by one man, though in practice the bulky ammo pans required an entire section of men to keep the gun operating . Soon, the Lewis gun was seen to be useful in marching fire assaults, notably by the Australian Corps in the July 1918 Battle of Hamel . To serve the same purpose, the German Army adopted the MG08 / 15 which was impractically heavy at 48.5 pounds (22 kg) counting the water for cooling and one magazine holding 100 rounds . </P> <P> In 1918 the M1918 Browning Automatic Rifle (BAR) was introduced in the US Army, and with the 15.5 - pound (7 kg) weapon came new field tactics . For marching fire assaults, the BAR's shoulder sling was to be adjusted in length to allow the butt of the weapon to be held firmly at the side of the torso just above the hips, with one hand at the trigger and the other hand aiming . A recommended rate of fire was one round per footstep, with eyes kept on the target and the weapon aimed low at first . The tactic was to be employed under conditions of limited field of fire and poor visibility such as advancing through woods . </P> <P> The light machine gun directly affected the organization of the infantry, and, by the middle of 1917, put an end to the tactic of company - sized waves . Platoons and squads became important . </P> <P> The Imperial German Army deployed flame throwers (Flammenwerfer) on the Western Front attempting to flush out French or British soldiers from their trenches . Introduced in 1915, it was used with greatest effect during the Hooge battle of the Western Front on 30 July 1915 . The German Army had two main types of flame throwers during the Great War: a small single person version called the Kleinflammenwerfer and a larger multiple person configuration called the Grossflammenwerfer . In the latter, one soldier carried the fuel tank while another aimed the nozzle . Both the large and smaller versions of the flame - thrower were of limited use because their short range left the operator (s) exposed to small arms fire . </P>

During ww1 how did war focused economies changed the way industry operated