Why You Should Use Hollow-Point Ammunition in Your Carry Gun | Range365

Why You Should Use Hollow-Point Ammunition in Your Carry Gun

There's a reason most law enforcement agencies, including the FBI, use hollow-points—they make the most of a pistol round's power.

Premium self-defense ammunition isn’t cheap. In fact, it usually costs about a buck per round. There are plenty of good reasons for that and given the circumstances with which it might be used, you should be happy to fork over the money.

There are many good reasons why virtually every law enforcement officer in the country is equipped with hollow-point ammunition, and we’ll explore those in a minute. But here’s a hint. It’s not because hollow-points are more lethal. In fact, they are generally considered to be less lethal. Hold that thought while we explore this topic in more depth.

Self-Defense Ammo Criteria

At the highest level, premium self-defense ammunition has to do three things.

  1. It has to work every single time, possibly under the worst of conditions. Whether wet, dirty, hot, or freezing, it’s got to go bang when you most need it.

  2. It has to penetrate the target to an appropriate depth to cause enough damage to stop whatever aggressive behavior caused the user to fire it in the first place.

  3. It has to expand reliably under a variety of target conditions to maximize its fight-stopping effectiveness.

The last two items on this list are really about maximizing the effectiveness of relatively weak handguns. Unlike rifles and shotguns, handguns aren’t the fight-ending wonder weapons portrayed in the movies. Many people shot with handguns of any caliber continue doing whatever it was they were doing for a period of time - even after being shot. Police encounters have documented bad guys continuing to fight after being shot 10, 20, and even 33 times.

That’s certainly not the norm, but it does help set the stage for a discussion on why self-defense ammunition is so meticulously engineered to get every bit of possible performance. Why the need for expansion? If a bullet expands in the target it can do more damage, cause more bleeding and loss of blood pressure, and therefore (potentially) stop an attacker more quickly.

The last item on the handgun ammunition performance criteria list, expansion, is what leads us right to hollow-point ammunition. While there are some other variants of non-hollow-point defensive ammo on the market like Federal’s Guard Dog expanding full metal jacket, for purposes of this discussion we’ll limit ourselves to hollow-point designs.

Speer 9mm Hollowpoints

These two 9mm loads from Speer are classic hollow-point designs. The +P version on the left moves at higher velocity so you can see how the bullets expanded more completely.

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What is A Hollow-Point Bullet?

First, what is a hollow-point bullet? As the name implies, the tip is hollow and has a cavity cut or formed. The idea behind this is that when the bullet passes through liquid-like material at sufficient velocity, the pressure of the fluid inside the hollowed-out area causes the bullet material to push outward or expand.

Think of it like dragging a red Solo cup through a swimming pool open side first. If you move it fast enough through the water, the cup will eventually open to the point of ripping apart.

That’s what happens with a hollow-point bullet, although the “ripping open” action is carefully predicted so that the bullet opens to a larger diameter, but doesn’t shred itself like the Solo cup would.

That’s what happens with a hollow-point bullet, although the “ripping open” action is carefully predicted so that the bullet opens to a larger diameter, but doesn’t shred itself like the Solo cup would. Unless a hollow-point bullet strikes something hard, it’s unlikely to fragment. Contrary to popular myth, hollow-points do NOT expand while flying through the air!

Expansion and Penetration

So, hollow-points are designed to expand, causing their diameter to increase as they pass through the target. Acceptable expansion is considered by many to be 1.7x the original bullet diameter. As an example, a 9mm bullet has a diameter of .355 inches. If it expands to 1.7x its original size, then it travels through the target with a diameter of .60 inches.

Note the scoring around the cavity on the unexpanded bullet. These grooves help the bullet to open up at a predictable rate.

Note the scoring around the cavity on the unexpanded bullet. These grooves help the bullet to open up at a predictable rate.

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A .45 ACP projectile would measure just over three-quarters of an inch when expanded to the same degree. Some ammo will expand to nearly double its original diameter.

So why not design bullets that expand as much as possible? Because penetration and expansion work against each other. The more a bullet expands, the less it will penetrate due to friction. On the other hand, if a bullet doesn’t expand quickly enough, it can penetrate too much. This balance between expansion and penetration is a sophisticated act.

What makes it even tougher is that bullets need to perform within design parameters even though they might have passed through a variety of barriers in front of the target like clothing, glass, wood, or automotive steel. With so many potential variables, how to ammunition manufacturers optimize their designs?

The FBI Tests

Enter the Federal Bureau of Investigation. The FBI ballistic laboratories have developed a rigorous and carefully designed ammunition testing protocol to help them objectively compare the performance of different calibers and ammunition types.

When you consider the number of calibers, ammo companies, and unique loadings per manufacturer, it quickly becomes apparent that there are a nearly infinite number of variables. The FBI test protocols give the agency a way to compare.

While no lab test can accurately predict performance on the street, this test is generally considered the best overall approach and has been adopted industry-wide. Ammo companies design their offerings to excel in as many categories as possible in these FBI test scenarios. Let’s take a look at what’s involved:

Simulating Real-Life Situations

Since the FBI never knows in advance what the tactical situation on the street will be, they’ve designed the series of tests to simulate different situations. All fired projectiles ultimately end up striking a 6x6x16-inch block of 10% ballistic gelatin that is carefully calibrated to ensure accurate test results over time. What varies is what is in front of those blocks.

Barriers are put in place to simulate no clothing, heavy clothing, doors, walls, windows, and cars. Ideally, a bullet will expand and penetrate properly after passing through any of these barriers. Here’s the list of test scenarios.

Here’s the setup for auto glass barrier testing. Precise angles of glass to target are part of the FBI test specification to replicate a windshield.

Here’s the setup for auto glass barrier testing. Precise angles of glass to target are part of the FBI test specification to replicate a windshield. Cloth also covers the ballistic gel to simulate clothing.

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Most of the tests are performed from a distance of 10 feet, but a couple of the scenarios are replicated at 20 yards. The tests call for bullets to penetrate to a minimum of 12 inches and maximum of 18 and expansion is carefully measured. When you consider angles and the possibility of a bullet striking extremities first, the need for a bullet to travel 12 inches becomes clear.

In the Miami shootout of 1986, agents delivered what would have been fatal hits to the armed subjects had their ammo penetrated deeply enough. It didn’t, and partly as a result, two agents were killed and five wounded before the fight ended.


Over-penetration is seen as a drawback too. Not only does the agency not want to see bullets pass through targets and risk hitting bystanders, over penetration implies wasted energy that could have aided additional expansion. As a result, bullets that penetrate under 12 inches and over 18 are penalized in the scoring system.

The wide range of scenarios quickly weeds out the poor performing ammunition from the more sophisticated loads. Virtually any hollow-point bullet will expand properly when fired into plain gelatin—it’s the barriers that cause them to fail. Fabric, wallboard, and wood can “clog up” the hollow-point cavity and prevent expansion. Auto glass and steel can blunt the bullet and cause a similar result.

This Speer Gold Dot G2 9mm ammunition is used by the FBI.

This Speer Gold Dot G2 9mm ammunition is used by the FBI.

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Hollow-Point Alternatives

There have been a number of ammunition solutions to this plugging problem over the years that went beyond designing a better hollow-point bullet. Cor-Bon's Pow'RBall ammunition fills the cavity of a hollowpoint bullet with a polymer tip that prevents it from getting clogged with barrier material, but also allows it to expand. Federal Premium's Guard Dog ammunition uses a polymer filling and scored jacket to cause bullet expansion on impact, eliminating the need for a hollow point. Guard Dog rounds are designed especially for home defense and to minimize over-penetration as much as possible.

Some states, like New Jersey, outlaw the sale of hollow-point ammunition for unknown reasons and heavily regulate its ownership and use, which can make it something of a gamble for a law-abiding citizen to use in a self- or home-defense situation. Solutions like the Federal Guard Dog ammo are a great approach, since it offers virtually the same benefits as a hollow-point.

Bullet Alphabet Soup

Since we’re talking about different types of expanding bullets, it’s a good time to stop and explore some of the acronyms you’re likely to encounter.

HP: - Hollow-point bullet

JHP: - Jacketed hollow-point: Most often, HP and JHP are used pretty interchangeably. A JHP bullet is usually made of lead in the interior. A thin “jacket” is formed on the outside to help the soft lead make it through the barrel without deforming. The harder jacket material also keeps the lead from breaking apart inside and outside of the gun, and helps the bullet penetrate harder barriers.

Some hollow-point ammunition, like the Speer Gold Dot G2, currently used by the FBI doesn’t technically use a jacket. It’s still made from a softer lead interior, but rather than shaping a hard jacket around the lead, a copper “skin” is applied chemically that bonds to the lead. These bullets tend to stay together when fired through tough barriers can separate the lead interior and standard jackets—an important factor for law enforcement.

EFMJ: - Expanding Full Metal Jacket: The Federal Guard Dog ammo previously mentioned is a perfect example of EFMJ ammo. There is no hollow-point, yet the bullet still expands to a larger diameter when it impacts a target.

FMJ: - Full Metal Jacket: Like JHP ammo, most FMJ bullets have a soft lead core. With FMJ, the jacket covers everything (accept possibly the tip on some bullets) and there is no hollow-point to initiate bullet expansion. FMJ ammo is typically used for practice since it doesn’t expand and is a lot less expensive to manufacture, which is why it costs less on the shelf.

Federal Guard Dog Ammo

Some expanded Guard Dog bullets. Instead of a hollow-point, the flat-tipped bullet jackets are scored and filled with a blue polymer that causes it to expand when it hits a target.

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A Word on Lethality

To come back to the lethality issue, hollow-point ammunition isn’t designed to be more “lethal” than regular full metal jacket practice ammo. In fact, the opposite is truer. It’s designed to stop an aggressor as quickly and efficiently as possible.

If expanding ammunition can generate fight-stopping results quickly, then fewer shots are required to end a given confrontation. As the theory goes, fewer shots mean fewer holes, and that reduces the risk of the most common cause of gunshot wound death—blood loss. When it comes to real-world ballistics, it’s virtually impossible to prove anything, as there are endless variables, but there’s a reason nearly every law enforcement agency has moved to hollow-points.

Summing Things Up

Virtually every law enforcement agency in the country uses some form of hollow-point ammunition for a very good reason: it’s more effective at stopping attackers.

While no one wants to be shot with one, a single shot from a handgun isn’t going to knock a home invader through a wall. Compared to centerfire rifle rounds and even most shotgun ammo, handgun bullets are small and slow.

Speer Gold Dot self defense hollow-point ammunition in .38 Special.

Speer Gold Dot self defense hollow-point ammunition in .38 Special +P.

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Hollow-point ammo is intended to eke every bit of fight-stopping potential from handgun ammunition by magnifying the effect on the target. By making bigger holes and attempting to keep the bullet in the target as opposed to just passing through, all possible energy is used to stop the attacker. Conceptually, using cheap practice ammo in a defensive handgun for anything but practice is kind of like Indy 500 drivers using three-year old 75 octane gas in the big race. In reality, they’d carefully choose the fuel that will give them every possible advantage in terms of speed, reliability, and performance. When it comes to protecting yourself and your family, you should do the same.

Cycle Your Defensive Ammo

Premium ammo will last for a long time, but it’s always a good idea to cycle it through your handgun once a year or so. Shoot it at the range, clean your gun, and reload it with fresh defensive ammo.

Some older (or less expensive) guns can have problems feeding hollow-points, as they were designed for round-nosed FMJ bullets.

Some older guns can have problems feeding hollow-points, as they were designed for round-nosed FMJ bullets.

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Make Sure Your Ammo Works in Your Gun

One other important point: when you choose your defensive ammo, you need to make sure it functions reliably in your gun. Before you bet your life on it, you need to know that it will feed properly in your handgun and not jam.

Some older guns can be a bit finicky with hollow-point ammunition, since they were originally designed for FMJ ammo with nice round nose shapes that feed easily. You’re going to have to open the wallet and invest in some test rounds—the more the better. Most trainers recommend making sure your gun will fire a couple of hundred rounds flawlessly before settling on a defensive ammo choice. If your budget doesn’t allow that, do as much as you can being sure to test when shooting two-handed, strong handed, and one-handed with your support hand.

Next time you get sticker shock from the price of your self-defense ammunition, think about all that goes into its design, testing, and construction. Making bullets that work properly across all of these scenarios isn’t a simple thing.


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