In the past two decades Americans have experienced a turbulent relationship with guns. We are compelled as a society to love them through popular culture and are taught to hate them through the acts of newsworthy criminals. Through all this, it is easy to view guns as a living force by which we can be either entertained or physically threatened. In reality, firearms are nothing more than engineered mechanical devices, capable of acting in ways both defined and directed by human beings. It is the intention of this article to explain the functionality and design of firearms so that we may come to better understand exactly what they are and are not capable of doing.
Introduction
The history of the firearm stretches back to the middle ages. An exact date is uncertain, but they are reported instances of firearms being used as early as the middle of the 14th century. At that time guns were little more than a wrought iron or bronze tube a few feet in length, closed at the breech and left open at the muzzle (Peterson, 9). This "hand cannon" was loaded by pouring gun powder down the barrel packed tightly with a rod or stick, then inserting a round projectile on top. It was fired by igniting a small amount of powder placed in the touch hole-a hole drilled into the breech-that in turn ignited the main charge and propelled the projectile through the barrel. These early weapons likely served little practical purpose other than frightening whomever they were being fired at; they frequently failed, producing a great deal of smoke and noise with wild inaccuracy.
However unreliable, firearms proved themselves useful, gaining wider usage as new designs and technologies have continuously emerged. The most important inventions that led to the creation of modern firearms were the percussion cap in 1807 and the introduction of the cartridge in 1851 (Heard 8-9). These two innovations, more than any others, paved the way for the current state of firearm technology.
Modern Firearms
The modern firearm exists in a myriad of forms ranging from simple single-shot rifles to complex self loading handguns. In its most basic form, the firearm consists of a barrel, an action, a firing mechanism, and a stock or grip.
Modern guns fire an improved version of the cartridge-type ammunition invented in 1851. This type consists of a metal tube called the case or casing, a bullet, a primer and a smokeless powder charge. Put together, this type of cartridge is referred to as center-fire ammunition.
Most firearms operate by exploiting the same basic physical and chemical laws - it is therefore useful to study these principles independent of the form that the firearm takes. The study of these principles is called ballistics and consists of three parts: internal, external, and terminal.
Internal Ballistics
Internal ballistics is the study of the flight of a projectile inside a firearm. This term is used by experts to refer to all aspects of the internal workings of a firearm from gases and pressure to rifling and bore erosion. As such, internal ballistics is a very large subject. Many books have been written to explain the complex physical and chemical processes that internal ballistics entails. Our main concerns when looking at internal ballistics will be the workings of the firing process, the purpose of rifling, and the causes of recoil.
