Bullets predate the modern firearms. In the beginning, bullets were made from stone or metal and propelled using a sling. After the advent of firearms, these were propelled by the explosion power of gunpowder. Over the next few centuries, bullets underwent little change—they remained the same spherical led balls with changes only in the dimensions.
Conical bullets came into use in the first half of the nineteenth century. Initially, cone shaped bullets came with a hollow cavity in the rear which was fitted with an iron cap to aid the bullet to grip the rifling grooves of the barrel. Conical bullets were soon found to be more accurate as their flight was much steady.
The modern bullet has its roots in the copper jacketed bullet that was invented by Major Rubin in 1883. Copper jacketed bullets could resist higher muzzle velocities as copper has higher melting point and durability when compared to lead. Bullets made of lead, when fired at higher muzzle velocities, tend to suffer surface damage and deformation.
The next advance came in the form of the Spitzer bullet. Unlike other bullets of that time, this bullet has an aerodynamic shape which imparted it with higher ranges and accuracy. Spitzer bullets when used with machine guns enhanced the lethality of war manifold.
The ultimate advance in bullet technology came with the development of the boat tail. The boat tail is a streamlined base for spitzer bullet that allows air to flow around the base of the bullet. This decreases the air-drag and makes the bullet very accurate in its trajectory. All the modern bullets are based on the same design albeit with slight modifications in design and material used to make them.
A variety of materials are employed to make materials. Initially, lead was the metal of choice for casting bullets. Lead bullets were well suited for making bullets with low muzzle velocities. In addition, it was also cheap and easy to mould which made it ideal to make bullets. However, as the need for higher muzzle velocities was felt, better metals and materials had to be investigated.
Copper jacketed bullets solved some of the problems associated with pure lead bullets. In addition to copper, other alloys of copper such as cupronickel were are also used to make bullets. The copper jacket, being much harder than lead, provides protection to the inner lead core. In some modern bullets, synthetic materials such as Nylon or Teflon may also be used as jacket material.
In bullets designed for piercing armour other metals may also be employed in addition to lead and copper. Armour piercing bullets are commonly made by using very dense metals such as tungsten, steel or depleted uranium. Because of the high density of these metals, a high amount of kinetic energy gets imparted which penetrates even thick armour. Incendiary bullets, on the other hand, have an explosive material at the tip which explodes upon impact. These bullets are designed to ignite munitions or fuel in the target area.
Other special purpose bullets such as tracer bullets have chemical substances that produce a bright coloured light when ignited. Usually magnesium perchlorate and strontium salts are used to impart bright colour which gives the shooter an idea about the trajectory of the bullet.
Bullets used for target practice and training may be made from materials such as rubber, plastics, wood and wax. Because of their low density and low speed, their effective range is very much limited. Rubber bullets may also be used in riot control and to subdue suspects without risking fatality. Blank rounds, on the other hand, do not have a bullet at all. Materials such as wax or paper are used to sustain pressure which produces noise to simulate a live bullet.
What the bullets of the future will look like is a matter of conjuncture and imagination. However, it can be certainly predicted that the future bullets will not be just metal slugs but rather intelligent electronic devices that can change the trajectory in mid-flight. They may even be capable of hitting targets on their own in a “fire and forget mode” and may be even capable of evading obstacles in their path. Technological progress in the fields of computers and artificial intelligence may are sure to affect bullet technology of the future.