Weapons That Changed The World: The French Lebel Model 1886.
This rifle revolutionised infantry small arms and overnight made every other rifle obsolete due to two major changes to the cartridge and bullet the Lebel rifle fired. The French Lebel 1886 rifle was the first of its kind to fire a cartridge containing smokeless powder, as well as an 8mm full metal jacket. The full metal jacket allowed the bullet to have a greater muzzle velocity without leaving traces of lead within the barrel of the rifle. However it crucially also used smokeless powder, this was three times more powerful than the black powder firearms currently being used by other countries. This meant that the 8mm bullet fired from the Lebel rifle had an effective range that was practically double that that of other rifles used at this time. Using smokeless powder also meant a solider carrying the Lebel rife could remain virtually invisible to an enemy at longer distances when firing, but could locate an enemy at any range by the smoke from their rifles. This obviously had a huge impact on infantry warfare.
These seemingly small changes revolutionised infantry small arms development for decades to come. This revolutionary design threw the entire world into an arms race, as many countries like Germany and the British Empire tried to catch up with the French.
This weapon was eventually replaced by the French army in 1909 due to further advances to the cartridge and rifling; but was still very common with the French infantry in the First World War and even saw some limited usage during the Second World War.