Welcome back to our Ammo 101 series where we are discussing everything you need to know about shotshell, handgun, rifle, and rimfire ammo. 

In this article, we are discussing rifle ammunition. Rifle ammunition has several centerfire and rimfire options.

Centerfire means that the primer, the component that ignites the powder and sends the bullet downrange, is in the center of the cartridge’s base. This is different from rimfire ammunition where the primer surrounds the entire rim of the cartridge’s base. For more information on rimfire ammunition, please refer to our Rimfire: The Perfect Intro to the Shooting Sports blog. 

How does rifle ammunition work?

Pulling the trigger of a loaded rifle releases the hammer or striker and sends the firing pin forward causing it to strike the primer, creating a mini explosion that ignites the powder. The ignition of the powder generates a gas that rapidly expands in the case, forcing the bullet from the case and down the barrel of the rifle. 

Fig.1 – For more information on Shotshell, Handgun, Rifle, and Rimfire ammo, view our Ammo 101 Graphics. 

The construction of rifle ammunition can be broken down into four components: primer, powder, case, and bullet. These four components, together, are referred to as a round or cartridge.

1. Primer – The primer is responsible for igniting the powder. 
2. Powder – Smokeless gunpowder is the propellant that the primer ignites and begins the process of sending the bullet downrange. 
3. Case – The case holds it all together. Cases can be made of brass, steel, or nickel-plated brass and serve as the housing for the primer, powder, and bullet. 
4. Bullet – A rifle round or cartridge contains a single projectile called a bullet. A bullet, made of lead with an outer jacket made of copper, is the component of a cartridge that will hit the target after the rifle is fired. There are different styles of bullets that we will talk about later in the article.

What information is on a box of rifle ammunition?

Take a look at the graphics below to understand what each piece of information on your new box of rifle ammunition means. We’ll break down the most important terms throughout the rest of the article.

Fig. 2 – Graphic breaking down the information found on a box of target rifle ammunition

Let’s talk caliber and cartridge

Keep in mind that the information in this section is for informational purposes only. To determine what ammunition you need for your rifle, refer to the stamp on the barrel or chamber of your rifle, check your owner’s manual, then match that to the cartridge name listed on the box of ammunition you purchase at the store. It is critical to your safety and the operation of your firearm to use the correct cartridge.

Fig.3 – Winchester Repeating Arms Model 70 rifle chambered in 30-06 Springfield and Winchester Ammunition Expedition Big Game 30-06 Springfield hunting ammunition. 

Now, let’s get into the technical explanation of caliber. Simply put, caliber refers to the inside diameter of a rifle’s barrel. Depending on what part of the world a cartridge was developed, some calibers are expressed in inches and others are expressed in millimeters. For example, a .308 caliber is expressed in inches whereas a 5.56 millimeter (5.56mm) is expressed in millimeters, obviously. 

It is important to note that caliber is simply a measurement. Firearms are designed to shoot specific cartridges, not calibers. For example, a .308 Winchester and 30-06 Springfield bullet are both .30 caliber bullets. However, the .308 and 30-06 are different cartridges that cannot be fired from the same rifle. A cartridge is defined by the caliber of bullet, total length, and the amount of propellant. 

Bullet Weight 

The number you see after the cartridge name on a box of ammo is the weight of the projectile or bullet. Bullet weight is measured in grains, for which the symbol is “gr”. Grains is a unit of measurement equal to 1/7,000^th of a pound or 1/437.5^th of an ounce. The higher the number, the heavier the projectile is. 

Bullet weight is one factor that affects the projectile’s velocity, trajectory, and impact energy, a trio of values also known as “ballistics”. 

Are you purchasing ammunition for hunting, plinking, long range competition shooting? When thinking about what bullet weight you should choose, it is important to determine what the end use will be. 

Bullet Types and Materials

There are several different types of bullets and materials used to make them. Always check with your local laws before purchasing as some states and cities restrict certain types of ammunition.

Bonded Bullet – Bonded bullets consist of a lead alloy core that is chemically or molecularly bonded to the jacket of the bullet. This ensures that the core does not separate from the jacket and the bullet’s maximum weight is retained upon impact. This type of bullet is designed for maximum penetration making it an extremely effective for big game hunting applications. 

Full Metal Jacket (FMJ) – FMJ bullets are lead projectiles that are fully jacketed with copper alloy. These bullets are typically used in target and training ammunition as they are less expensive and available in larger quantities. 

Soft Point – Soft point bullets are similar to full metal jacket projectiles; however the tip or “point” of the bullet is exposed lead. The exposed lead allows the bullet to expand upon impact, making it one of many popular bullet types for hunting. 

Ballistic Tip – Ballistic tip bullets are a jacketed hollow point bullet with a polymer tip inserted in the hollow point cavity. These are popular for long range hunting applications as the polymer tip improves the aerodynamic characteristics of the bullet.  Upon impact, the polymer tip is forced into the hollow point cavity to initiate expansion.

Jacketed Hollow Point (JHP) – JHP bullets are also made of lead, but JHP bullets have a jacket made of a copper alloy. JHP ammunition is best suited for personal defense and some hunting applications.

Open Tip – Open tip bullets are used as a target shooting ammo and are known for being highly accurate. They are similar to jacketed hollow point bullets; however bullet jacket is formed down to a smaller diameter hollow point, which is referred to as the open tip. This design makes these bullets accurate at long ranges and therefore popular amongst competition shooters.

Fig. 4 – Winchester Ammunition USA Ready® .308 Winchester Open Tip ammunition

Common uses of Rifle Ammunition

Now that we have an understanding of rifle ammunition, let’s take a look at how it is commonly used. 

• Hunting – There are some states and hunting seasons that allow for hunters to use a rifle in pursuit of game. Always check and follow your local laws and regulations before  hunting with a rifle.
• Target Shooting – Target shooting with rifles is a fun activity. It is also a great training opportunity for those that hunt with a rifle to sharpen their skills and maintain dilligent marksmanship.
• Competitive Shooting – There are several rifle shooting competitions that exist. The best part? They are open to anyone who wants to try! If you’re interested in competing with other rifle shooters, look for a local competition to get you started. 

While the world of ammunition can be a bit much to absorb, it’s important to learn at your own pace. It’s important to research topics, ask questions of qualified instructors and then put time in a the shooting range, when ready.  Be safe, have fun, and make the shooting sports a part of your life.