Summary: Gun Powder

During the Tang Dynasty in China, around 850 AD, alchemists working on making a concoction to make human beings immortal, accidentally created Gun Powder that they called “huo yao”. This was a mixture of Saltpetre (Potassium Nitrate), Charcoal and Sulphur that was gradually tuned in a ratio of 75%, 15% and 10% respectively. The Chinese employed this newly invented mixture in arrows, primitive grenades and mines to terrorise the Mongols as early as 904 AD. They tried to conceal this invention but eventually the secret formula was exported via the Silk Route to India, Middle East and Europe, leading to new weapons being introduced (Szczepanski).
Initially, the Chinese used hollow bamboo tubes filled with explosive gunpowder. A spear was then

Projectiles of cylindrical shape could be used with a rifled barrel and more amount of explosive powder could be packed in this shape and allowed greater kinetic energy to be imparted to the projectile (Krebs 272-74). The next main problem that needed to be resolved was facilitating the hard iron or steel shot to take the rifling. The method adopted to overcome this was to surround the projectile with a band of softer metal, like an alloy of copper that could adapt to the shape of the grooves of the rifling and in this process also allowed effective sealing of the bore. Thus, rifling overcame the issue of “windage” that was leak of gases in case of the smooth bore cannons, since the shot was muzzle loaded in a smooth bore and had to a size smaller than the muzzle itself (Weir 131). The force of a projectile is directly linked to KE given to it and is equal to 1/2 〖MV〗^2 where M is the mass and V the velocity. The two ways used to enhance it were to increase the "calibre" of the weapon i.e. the diameter of the bore of the barrel and the second way was enhancing the velocity imparted by the modern gunpowder, this has a greater impact as KE, as it is the square of velocity

The force exerted on the projectile and the cannon, by the gunpowder explosion is the same. However, there is a major difference in the mass of the two objects and therefore, the acceleration experienced by the smaller object, the projectile due to this force has to be of a much greater intensity to balance the above equation. This makes it travel hundreds of metres as compared to the cannon, which moves a fraction of a metre due to the recoil (White). This recoil caused a problem for large calibre guns and when a gun was fired, the heavy projectile exerted a stronger backward force. As a result, the castings would end up exploding due to recoil near the breech. The initial solution to the problem was to mount cannon on wheels to dissipate the recoil as cannon rolled backwards. In the later stages, recoil cylinders were used to absorb the recoil. In 1897, the French 75, used an oil cylinder with a piston that was attached to the barrel of the gun, this cylinder had a small opening attached to another cylinder. When the gun recoiled, the oil pushed back a floating piston in the other cylinder compressing the air in it. The work done in squeezing the oil in the first cylinder absorbed most of the recoil. When the recoil stopped, the compressed air in the second cylinder exerted pressure to