Bullets: Basics

After reading up about different types of propellants, we will now study the history of bullets. It may come as a surprise to some people to realize that the history of bullets predates the history of firearms. Bullets have been found in some of the ancient ruins around the planet. These bullets were not fired from firearms, but were fired from slings and handheld catapults. Some of these bullets were made of stone, others were made of metal.

The word "bullet" derives from the French word, boullet, which means "little ball". A lot of the early bullets were spherical balls and it wasn't until the 1820s or so when the bullets started to change shape.

When it comes to bullets for firearms, one thing is common to all of them, whether they were made in the 1200s or in the 2000s. A majority of them have a large percentage of lead. There are a few good reasons why this is the case.

In order to be a good bullet making material, the following characteristics are desirable:

1. Density: The bullet must be made of dense material so it can pack as much mass as possible in a given volume.
2. Low cost
3. Easy to shape
4. Availability of materials.

Lead seems to fit all these features admirably for small arms ammunition. By looking at the periodic table of elements, the reader will be hard pressed to find another element that is plentiful in nature, but has a higher density than lead. The elements above lead in the periodic table are either rare, volatile, gaseous, radioactive, expensive to extract from the ore or a combination of these properties. For instance, tungsten and uranium are denser than lead, but they are expensive to produce and harder to machine than lead. Hence people use depleted uranium and tungsten only for making special armor-piercing ammunition, but not regular small-arms ammunition. By contrast, lead is very easily available in nature, has high density and is a soft material with a low melting point (which makes it easy to shape). As an extra bonus, it is also a toxic substance.

One of the problems of lead is that it is a soft substance. With firearms before the 1800s or so, this wasn't a problem because the propellants used weren't as powerful and hence the pure lead bullet worked just fine. As propellants got more powerful, the soft lead bullets would get deformed too much before they left the barrel and they would also melt a bit due to the heat. These deformations affected the flight of the bullet. The solution was to encase the lead in a jacket of a harder material such as steel, cupronickel, copper etc.

In the next few posts, we will study the evolution of bullet development.