The world of ammunition is … large, to say the least. There are four different categories of ammunition: shotshell, rifle, pistol, and rimfire. Within those categories are an incredible amount of products all designed for different end uses, such as hunting, personal defense and competitive and recreational shooting. In this article, we will cover handgun ammunition. 

While there are plenty of handgun models chambered for rimfire ammunition, the most popular type of handguns used by individuals use centerfire ammunition.

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 handgun ammunition work?

Pulling the trigger of a loaded handgun 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 handgun. 

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

The construction of handgun 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 handgun 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 pistol is fired. There are different styles of bullets that we will talk about later in the article.

What information is on a box of handgun ammunition?

Take a look at the graphic below to understand what each piece of information on your new box of handgun 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 handgun 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 particular handgun, refer to the stamp on the slide or chamber of your handgun, 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 – Springfield Armory Echelon chambered in 9mm and Winchester Ammunition 200 round range pack of 9mm Luger cartridges. Note: 9mm Luger and 9×19 or 9x19mm Parabellum are the same cartridge, only with different names.

Now, let’s get into the technical explanation of caliber. Simply put, caliber refers to the inside diameter of a pistol’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 .22 caliber is expressed in inches whereas a 9-millimeter (9mm) 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 9mm bullet is the same diameter as a .380 ACP bullet, technically making them the same caliber. However, the 9mm and .380 ACP are completely different cartridges. A cartridge is defined by the caliber of bullet, total length, and the amount of propellant. 

+P Ammunition 

An additional piece of information you might find when looking for ammunition is something called +P.The +P designation is typically found just after the cartridge name (e.g. .38 Special (+P)). The +P designation means a cartridge is loaded to generate a higher chamber pressure during ignition than a standard cartridge. 

The higher chamber pressure increases the velocity of the bullet exiting the barrel and the higher velocity increases the energy transfer to the target. For example, a standard 9mm bullet exits the barrel at 995 feet per second (fps) and delivers 323 foot-pounds (ft lbs) of energy at impact. A 9mm bullet from a +P cartridge exits the barrel at 1,200 fps and delivers 396 ft lbs of energy at impact. 

+P ammunition options are primarily found in personal defense ammunition cartridges because most personal defense ammunition is used in handguns with short barrels. The higher pressure compensates for the lower muzzle velocity produced by short barrel handguns. 

Keep in mind that +P ammunition does result in more felt recoil than standard pressure cartridges. 

Always check your owner’s manual to ensure that your firearm is capable of firing +P ammunition and seek out instruction from a qualified firearms instructor to determine if +P ammunition makes sense for your personal defense plan. 

Fig. 4 – Winchester Ammunition Defender® 9mm Luger +P ammunition 

Shot Weight

You’ll notice on the box of shotshells in fig. 2 there is the measurement 1 3/8 oz. This refers to the shot weight. The ounce weight in shotshell ammunition represents the total weight of the shot material contained in the shotshell. There are different shot weights available in the world of shotshell ammunition and these weights influence the pattern, range, and recoil of the specific load. 

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”. 

When it comes to pistol ammunition, bullet weight can be helpful to understand as you experiment to find the ammunition that gives you the best performance out of your pistol. For example, your pistol may not cycle 115 gr, 9mm reliably due to the stiff recoil spring used by the pistol manufacturer, but 147 gr, 9mm cycles perfectly. It is often faster, easier, and cheaper to experiment with different bullet weights than it is to customize your pistol to shoot a specific ammunition. 

Fig. 5 – Winchester Ammunition Silvertip® 9mm Luger 147 grain JHP bullet

Bullet Types and Materials

There are few 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.

• 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 are not suited for personal defense. 
• Hollow Point (HP) – HP bullets are entirely made of lead with a hollow cavity at the top of the bullet to provide expansion upon impact. Although increasingly less common, lead HP ammunition is often used for target shooting and select hunting purposes.
• Jacketed Hollow Point (JHP) – JHP bullets are also made of lead, but JHP bullets have a jacket made of a copper alloy or a nickel plated jacket like you’ll find in Winchester Silvertip® ammunition. JHP ammunition is best suited for personal defense and some hunting applications.
• Semi-Jacketed Hollow Point (SJHP) – SJHP bullets are a lead bullet that is about 75% jacketed leaving the top exposed. This style of bullet allows for controlled and delayed expansion which is beneficial when using for personal defense against big game like bears in the backcountry. 

Fig. 6 – Winchester Ammunition Big Bore™ .44 caliber Semi-Jacketed Hollow Point ammunition

Common uses of Pistol Ammunition

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

• Personal Defense – Pistols are one of the most common firearms purchased for personal defense use. There are several types of personal defense pistol ammunition available. 
• Target Shooting – Target shooting with pistols is fun and challenging. It is also a great training opportunity for those that carry a pistol for personal defense to sharpen their skills and maintain dilligent marksmanship.
• Competitive Shooting – There are several pistol shooting competitions that exist. The best part? They are open to anyone who wants to try! If you’re interested in competing with other pistol shooters, look for a local competition to get you started. 
• Hunting – There are some states and hunting seasons that allow for hunters to use a pistol in pursuit of game. Always check and follow your local laws and regulations before  hunting with a pistol.

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 at the shooting range, when ready.  Be safe, have fun, and make the shooting sports a part of your life.