How Does A Bullet Work?

Guns (firearms) are without a doubt some of the most common weapons found on our planet today. They range in size, style, and usage, but they all have one thing in common: bullets.

The bullet is truly an extraordinarily simple concept. By definition, the modern bullet is a steel ‘penetrator’ core surrounded by a heavier metal such as lead. Some bullets are tipped with a harder substance such as tungsten carbide in order to achieve maximum penetration, while others are designed to expand on impact, guaranteeing maximum damage as they pass through a target. Moreover, while there are as many styles of bullets as there are purposes for using them, the physics working behind the scenes remains relatively constant.

Today, most bullets come as part of a cartridge. In a cartridge round, the bullet is usually located atop a brass casing which houses the propellant and a primer/firing cap. The amount of propellant present is usually directly proportional to the size of the bullet, which itself is dependent on the task that the cartridge is designed to perform. Larger bullets generally pack more ‘punch’, but their slower flight time and increased ballistic coefficients limit accuracy. Smaller rounds tend to have higher muzzle velocities, but often lack the penetrating power of their larger cousins. Like many things in life, it is a system of tradeoffs; the trick is striking the right balance for the task at hand.

Cartridges are simple, but the devices used to deliver them to their targets can be less so. Firearms, in general, are manufactured to utilize a specific size and style of cartridge. Although they utilize a variety of loading mechanisms, some more complex than others, once a round is ‘chambered’ the processes involved are universal. When the trigger is pulled, a small firing pin strikes the primer at the base of the cartridge, causing a spark that ignites the primary propellant. The volatile propellant releases massive amounts of energy and superheated gas as it combusts, forcing the projectile at the end of the brass casing forward at immense speeds. As the bullet passes through the barrel of the weapon, grooves etched in the barrel walls cause the projectile to spin as it leaves the muzzle, thereby stabilizing its flight and trajectory.

Once in the air, a bullet immediately begins loosing velocity. However, because the projectile is so small, and is travelling at such high speeds, it maintains massive amounts of kinetic energy all the way to its target. In fact, some specially designed bullets and their firearm counterparts can fire projectiles that retain lethality, if not accuracy, at distances significantly larger than a mile, while handguns are only effective out to a few hundred meters. Nonetheless, no matter how far away a target is, or what type of round is being used, the effects of a bullet strike are often gruesome and nearly instantaneous. Causing immense damage to whatever it happens to strike, the modern cartridge round reinforces a basic tenant that we often seem to forget:

Sometimes the most effective solution is the simplest.