Various types of ammunition lined up next to each other

Types of Ammo: How to Choose the Right Kind

Knowing which type of ammo to buy for your custom gun can be challenging. This can be especially true if your favorite weapon does double duty, such as when you use a weapon for both home defense and as a ranch gun. Just as more and more gun manufacturers seem to pop up every year touting models with new features or an innovative design that may or may not reinvent the wheel, so, too, do ammunition makers offer an ever-increasing myriad of options, many of which seem to have only minor differences from other round offered by the same manufacturer or their competitors. The cartridge you shoot can be a very personal choice, as every shooter (and their weapon) will have different preferences, but understanding the types of ammunition available and what they are designed to do best can help you find the right fit for your shooting needs.

What Do You Want Your Rounds to Do for You?

Hollow point ammunition with two magazines

The first step to choosing the best ammo is understanding what you need the ammunition to do. Not all cartridges are created equal. Each different round is built to meet certain specifications and parameters that affect how the bullet performs when in your weapon, as it flies through the air toward the target, on impact, and after the bullet has hit the target. First, we’ll talk about the performance parameters you should be considering to narrow down your search for types of ammo, and then we’ll look at the specifications on ammo boxes that will help you pick the right one.

  • Velocity – The speed at which a bullet travels is going to affect how you sight in your precision optics and aim your weapon. Guns fire their bullets in an arc, with the bullet rising before gravity drags it back downwards. Faster speeds extend this arc while also imparting more kinetic energy into the projectile, while slower speeds shorten this arc.
  • Terminal Performance – At the far end of its flight, the bullet impacts the target, transferring its energy. One of the primary considerations in selecting the best gun ammo is what happens next. Whatever type of ammo you choose, this terminal performance can be broken down into penetration and expansion to prioritize the characteristics you’re looking for.
    • Penetration – When the bullet hits the target, its mass wants to keep going in a straight line. This can carry it into or even through the target, where it will continue its flight. In some situations, this is the intent, and the bullet may be carried through a paper target into a bullet trap or through a barrier to strike a target behind it. In others, this can be incredibly dangerous as the target may alter the trajectory of the bullet in unpredictable and dangerous ways or fail to transfer enough energy to stop a threat, putting yourself or others at risk.
    • Expansion – Expansion refers to the change in a bullet’s shape as the kinetic forces smash the bullet into the target. This can help the bullet deliver even more of its energy into the target faster but this may come at the expense of penetration.

Reading the Ammo Box

When you get ready to buy your ammo in person, you’re usually confronted with a wall of boxes facing you end-on with various specifications printed on them. If you’re buying online, this information is still usually available on the product page. Learning to decipher this information is important to making sure you have the right type of ammo for your weapon and shooting needs.

  • Caliber/Gauge – The weapon’s caliber or gauge is probably what most gun owners can pick out the easiest. This is often either expressed as a decimal denoting the diameter of the caliber in inches (.38/.357/.45), millimeters that express the diameter or diameter and length of the cartridge (9X19mm, 10mm, 7.62X39mm), or as a one or two-digit gauge (12-guage or 20-gauge). There may be letters or words also added to differentiate one similar round from another (.22 vs. .22 Long vs. .22LR vs. .22WMR).
  • Pressure/+P/+P+ – After the caliber designation, you may also see a +p or +p+ symbol. The +p denotes positive pressure loads where additional gunpowder is loaded in each cartridge beyond the standards set for normal pressure rounds of that caliber, increasing velocity and kinetic power. These are seen primarily in modern pistols like the Glock, although increasingly legacy rounds using higher pressures are being created for today’s versions of formerly underpowered calibers like the .38SPL. Rounds designated +p+ are rare but feature even more powder. Not all guns are made to handle the increased pressure created by these rounds when fired.
  • Weight – Weight is expressed in grains and refers only to the weight of the projectile used in the cartridge. Heavier bullets travel slower than their lighter counterparts and have less mass to deliver their kinetic energy to the target.
  • Type of Bullet – Not all bullets are made the same, and the type of bullet loaded into the cartridge can have a big impact on the type of ammo for your needs. Most bullets feature a soft metal core, often lead, that may be surrounded by a harder metal that helps it withstand the explosive pressures of firing your gun without deforming or leaving too many deposits inside the weapon. These usually are indicated by a shot designation in the case of shotgun shells, like 000 buckshot, or by an abbreviation:
    • LRN/LWC – Lead round nose and lead wadcutter rounds have no metal covering the soft lead core and are seen on low-pressure caliber weapons, like the .38SPL.
    • FMJ – Full metal jacket rounds enclose the lead core completely in a metal covering, often copper or brass. These bullets are resilient in flight and on impact.
    • JHP – Jacketed hollow points use a lead core partially covered in a metal jacket. The tip is hollowed soft lead, increasing expansion on impact, while the partial jacket allows for high-pressure loads and accurate flight.

While these are the most common bullet types seen, a myriad of specialty ammo exists that will be plainly spelled out, such as frangible, flechette, and other exotic rounds.

Types of Ammo to Look for By Purpose

9mm Glock (slide locked back) with spent and unspent shells

One of the challenges when selecting ammunition is that there are many different types of ammo that fit specific needs. Some do it better than others across the board, while others do it better based on your weapon and shooting preferences. The following is to give you a few general guidelines to get you started.

Target Shooting

Target rounds need to be a similar speed and weight to your carrying rounds, but the primary ballistic consideration will be accuracy. You want a cartridge that will shoot straight through the target and into the bullet trap or berm behind it. FMJ rounds are a popular choice for modern high-pressure pistols, while older wheel guns with lower-pressure cartridges can easily use LRN or LWC rounds.

Personal Defense

Personal defense weapons, whether for home or concealed carry, are all about delivering a round with sufficient mass and speed to provide instant stopping power. When possible, +p rounds are a great choice, while hollow points will give you the expansion you need for a large wound channel and quick energy dump without over-penetrating like their fully jacketed counterparts.


Hunting rounds, like those used in your AR-15 rifle,  need many of the same characteristics as defensive rounds, but they need to do it at longer ranges against larger, heavier game. This means high-pressure, heavier-weight hollow points that can carry further through layers of tissue while still expanding. High-pressure FMJ loads can over-penetrate, failing to deliver the stopping power you need, and lighter loads may be stopped in the body too soon, painfully wounding the animal. These hollow points, often found in rifles and large-caliber handguns, are similar to their smaller counterparts but have more metal behind the soft lead core to help the expanded bullet reach vital organs for an immediately lethal wound.

Shotgun Loads

Shotgun cartridges come in a variety of loads. A good target load will be a 2¾” shell with No. 7 or smaller shot. This will allow you to practice for bird and small game. 3” and larger 000 buckshot load can be devastating in both hunting and personal defense situations, delivering multiple .32 caliber pellets down range.

Get Your Weapon Ready 

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