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Bullet Basics

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Over the past few years a lot of guns have been purchased by new shooters who know little more than pointy side goes in when it comes to ammunition. This article will help breakdown the components of a typical “round” of ammunition and highlight some of the features and options to know when selecting ammunition. The purpose of a bullet is to penetrate a target and is propelled by a firearm into space by the exertion of force created by a controlled chemical reaction. The word “bullet” translates to “little ball.” And is seated atop a cartridge that has a composition of different parts. A modern cartridge is made of the bullet, the case (this holds the composite parts of the cartridge together like a “shell”), propellant (typically gunpowder), the rim, and the primer which sets off the propellant. 

A primer is the small button on the flat end of a cartridge. When struck by the firing pin it creates a chemical reaction that emits heat which ignites the gunpowder causing a small explosion that launches the bullet. It is basically a metal cup that contains the explosive recipe that sets fire to the gunpowder. Today the two main types of primer systems are called Boxer or Berdan, named after the people who invented them. The main difference is that Boxer style primers can be easily removed so the shell casing can be reused. On the other hand, the Berdan style primer is difficult to remove and is typically avoided by reloaders.

The shell casing forms the body and packages the primer, gunpowder and bullet into a complete cartridge or round. At the base of the shell is the edged portion called the rim and is used in conjunction with the extractor located on the bolt carrier group to pull the expended round from the chamber. The casing itself is typically made of brass, steel, or aluminum with brass casings being the most popular choice. Steel casings are typically associated with Russian calibers and often avoided by shooters of non-Russian guns because of their hardness and ability to cause wear on the chamber and bolt components. Although aluminum is a lightweight option for ammunition it’s considered a poor man’s substitute for brass cased ammunition.


Gunpowder is the hidden ingredient that makes all the difference both ballistically and in keeping the gun from fouling and malfunctioning. Made from blend of saltpeter, sulfur, and charcoal, gunpowder can be tweaked to burn slower or faster. Measured in grains, basically the more grains there are the more powerful the bullet will be. Termed as being “clean” or “dirty” each time a round is fired it leaves a residue of burned powder inside the firing mechanism and barrel. This residue build-up is often the main culprit for weapon malfunctions and care should be taken to regularly clean your gun after extended usage. 

As far as bullets go, there are many different kinds and if you are a newbie about to purchase ammo all the variations can be confusing. Most bullets are composed of a solid lead core and a copper covering. This covering is called a “jacket” which is a word used to label several bullet types. The density, mold ability and mushrooming affect when hitting a target why lead is used. The different types of bullets are:

Full Metal Jacket (FMJ)bullets have a copper jacket covering the top of the bullet. This is common military and firing-range ammunition because it is inexpensive. It is aerodynamic which makes it good for long distance projection. It is not recommended as hunting ammunition because its design makes it more likely to pierce all the way through the targeted animal without mushrooming requiring follow-on shots. It also tend to pierce the target and continue to fly and potentially injure someone else.

Hollow Point (HP) bullets are for hunting or personal protection. They have an open tip at the front of the bullet which is designed to expand once it hits a point of impact, leaving its target with major injury. This open tip also creates drag and is not good for long distance shooting.

Soft Point (SP): Basically a FMJ with an unjacketed or raw lead nose. This actually makes the bullet more malleable when it hits a target and can change the shape upon impact. Soft points are typically the go to round for hunters of medium and large game.

There are many other styles of bullets but the three listed above are the most commonly used by hunters and self-defense shooters and have stood the test of time as being reliable and predictable in their intended use and function.

Ballistics is the mechanical study of flight, projectiles, and their movement under the force of gravity. A function of many variables including bullet weight, grains of gunpowder, barrel length and rifling. It is the study of how a bullet reacts to its surroundings as it travels. A science and an art, suffice it to say commercially available ammunition will often have a chart available to help the shooter determine the point of impact and force available at various ranges. This information is used to either adjust the sights or adjust the point of aim at various ranges in order to hit the target.

Hopefully this short article will help a new shooter understand the components of a cartridge some of their characteristics and the terminology used when discussing ammunition.