were in the rear) and 104 howitzers of 155 mm C TR model 1904 (C TR for "short rapid-fire", nicknamed 155 mm Rimailho. Rifles From 1915, the Berthier Mle 1907/15 rifle replaced the Lebel Model 1886 rifle, it had a three-round magazine. Later this rifle is also modified into a Berthier Mle 1916 rifle to use five-round magazines. Machine Guns When war broke out in August 1914, the French models of machine gun in existence were the St. Étienne Mle 1907 and the Hotchkiss M1914. The Saint-Etienne machine gun was gradually abandoned because it was considered too fragile for use in trench warfare and disappeared from the front lines in 1917. It was replaced by the Hotchkiss machine gun, which was gas actuated and air-cooled. This machine gun allows two types of fire, intermittent fire or automatic fire, it has a rate of fire of 450 rounds/min, it is fed by metal cartridge magazines of 24 rounds or by flexible belts of 300 rounds. At the start of the war, each infantry battalion's medium machine gun section had two guns, but this increased fourfold as the war continued. Machine gun companies were grouped at regimental and brigade level, with a similar practice being undertaken by the Infantry Branch of the Machine Gun Corps in the British Army. In January 1915, Joffre ordered research into a light machine gun to obtain significant firepower while being mobile. In 1916, the Chauchat machine gun was put into service, this lighter weapon had less staff to crew the weapon, semi-circular magazines of 20 cartridges with a potential rate of fire of 250 rounds/min. It has the possibility of firing by shot (60 to 80 rounds/min) or machine gun fire. This weapon allows for mowing and rapid changes of target, and has an accuracy equivalent to a machine gun up to 600 or 700 metres, after which the dispersion of fire is greater. Each infantry company was equipped with 8 of these light machine guns. Grenades The French army initially used stocks of model 1882 hand grenades, initially intended for the defence of forts. During 1915, many prototypes of explosive, suffocating, tear gas, incendiary and smoke grenades were tested on the front. These different grenades were categorised as the fuse type with a slow-burning fuse that caused the explosion 5 seconds after being triggered, or, the percussion type whose explosion was caused by the impact