What Are Hollow Point Bullets (And Why You Should Buy Them!)

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Hollow point bullets are a popular choice among law enforcement, self-defense practitioners, and hunters due to their specific design and performance characteristics aimed at maximizing impact and minimizing collateral damage. In this article, I will explain the basics of how hollow point bullets work, their purpose, andthe various types available on the market. I will also dive into the specifics of jacketed hollow points (JHP), the most prolific self-defense projectile on the market.

But First: Ballistics & Terminal Ballistics

Ammunition ballistics is the science that deals with the behavior of projectiles, specifically bullets, during their flight from the moment they are fired until they reach their target. This field is divided into three main categories: internal, external, and terminal ballistics.

Internal Ballistics: This pertains to the processes within a firearm that occur from the ignition of the gunpowder to the bullet's exit from the barrel.
External Ballistics: This focuses on the bullet's path through the air and the factors that influence its trajectory, such as gravity, wind, air resistance, and stability.
Terminal Ballistics: Terminal ballistics, on the other hand, refers to the behavior of a projectile when it hits its target. It is concerned with the effects of the bullet upon impact, such as penetration, expansion, and the transfer of energy to the target, crucial for understanding how ammunition will perform for hunting or self-defense. This understanding is especially important in the design of projectiles like hollow point bullets, which are intended to expand upon impact to maximize damage within the intended target without over-penetrating.

The main purpose of hollow point projectiles is to improve terminal ballistics. However, I'll discuss a type of projectile below that uses a hollow point to improve external ballistics.

What a Hollow Point Isn't

One of the most popular types of ammunition is the full metal jacket (FMJ). FMJs are particularly favored for practice and firing range sessions due to their lower cost compared to other types of ammunition. Typically, FMJ bullets are composed of a lead core encased in a copper jacket, which simplifies the manufacturing process and reduces costs. FMJs are primarily used for target shooting, as their design is optimized for punching holes in paper targets without the need for expansive terminal ballistics.

A selection of FMJ (full metal jacket) bullets

Let's first look at what hollow points aren't. This is a selection of FMJ (full metal jacket) cartridges. From left to right: .338 Lupua Magnum, 7.62x51mm NATO, 7.62x39mm, 5.56x45mm NATO M855, .45 ACP (Automatic Colt Pistol), 9x19mm Parabellum, .50 BMG (Browning Machine Gun) (back right).

What is a Hollow Point Bullet?

A hollow point bullet is designed with a hollowed-out shape at its tip, which causes the bullet to expand upon entering a target. This expansion is designed to increase the diameter of the bullet, creating a larger wound channel, transferring more energy to the target, and reducing the likelihood of over-penetration, which is crucial in both hunting and self-defense scenarios.

Here are someexamples of hollow point cartridges in popular calibers. From left to right: .223 Remington Jacket Hollow Point, .45 ACP (Automatic Colt Pistol) JHP (Jacket Hollow Point), .40 S&W (Smith & Wesson) JHP, 9x19mm Parabellum JHP, .22 WMR (Winchester Magnum Rimfire), and .22 LR (Long Rifle) copper-plated hollow point.

How Do Hollow Point Bullets Work?

The primary purpose of the hollow point’s design is to ensure that upon striking soft tissue, the bullet deforms. The front of the bullet expands, or "mushrooms," effectively increasing the surface area of the projectile as it passes through the target. This process maximizes tissue damage and energy transfer, which can be crucial for quickly neutralizing a threat or swiftly bringing down game.

Hollow point bullets are designed to transfer more energy to the target tissue than standard bullets, which simply pierce through it. This is achieved through a mechanism known as "hydrostatic shock," where the expansion of the bullet creates a pressure wave that disrupts surrounding tissue more extensively. This action results in an expanding cavity within the wound that exceeds the size of the bullet path before collapsing, thus affecting the nearby tissue and organs more severely.

Variations of Hollow Point Bullets

There are several variations of hollow point bullets, each designed to enhance certain aspects of bullet performance:

Standard Hollow Points: These are the basic form, designed to expand upon impact with soft tissue. They are typically used in self-defense situations.
Jacketed Hollow Points (JHP): These bullets have a metal jacket that partially covers the bullet, leaving the hollow point exposed. The jacket helps with penetration and controlling expansion when the bullet hits the target. JHPs are favored in law enforcement due to their reliability and effectiveness in stopping threats.
Polymer-Tipped Hollow Points: These bullets feature a plastic tip fitted into the hollow point to initiate rapid expansion upon impact. The polymer tip also helps the bullet maintain its aerodynamic shape during flight, improving accuracy.
Bonded Hollow Points: These are JHPs with a bonded jacket and core, which helps the bullet retain its weight and maintain its structure upon impact and penetration, making them highly effective for hunting larger game.

Various 9mm projectiles. From left to right: 9mm FMJ (Full Metal Jacket), Remington 9mm 124-grain BJHP (Bonded Jacketed Hollow Point), Georgia Arms & Ammo 9mm 124-grain loaded with Speer Gold Dot Jacket Hollow Point, Sellier & Bellot 9mm 155-gr Jacket Hollow Point.

How Jacketed Hollow Points (JHP) Work

Jacketed hollow points combine the advantages of a full metal jacket bullet with those of a hollow point. The jacket, usually made from copper or a copper alloy, helps the bullet maintain its shape during penetration, ensuring deep tissue penetration. Upon impact, the exposed soft lead tip expands, increasing the stopping power by creating a larger wound channel. JHPs are engineered to provide maximum efficiency in transferring kinetic energy to the target, thereby increasing the likelihood of a quick and efficient stop.

This product photo of US Cartridge 9mm 124-grain JHP Law Enforcement Contract Overrun ammunition shows how jacket hollow points "mushroom" (lower right of image) when striking tissue, transferring energy into the target.

Hollow Points & Precision Rifle Applications

An interesting exception to the typical terminal ballistics purpose of hollow point projectiles occurs in precision rifle shooting. Here, a very small hollow point is featured at the tip of the projectile, not for expansion upon impact but for aerodynamic efficiency that improves the projectile's external ballistics. As the bullet travels, a tiny air bubble gets trapped in this hollow point tip, effectively improving the projectile’s shape and increasing its ballistic coefficient during flight. This modification enhances the bullet's stability and accuracy over long distances.

.223 REM BTHP compared to 5.56x45mm NATO M855

Not all hollow points are designed for expansion! An example is the Winchester .223 Remintion 69 grain BTHP (boat-tailed hollow point) on the left, designed for precision accuracy. On the right: 5.56x45mm NATO M855.

Benefits of Hollow Point Bullets

Effective Energy Transfer: Due to their expansion, hollow points transfer kinetic energy to the target more efficiently than FMJ (Full Metal Jacket) bullets, which are more likely to pass through a target without transferring as much destructive energy.
Reduced Risk of Over-Penetration: The expansion reduces the risk of the bullet passing through a target and causing unintended damage or injuries.
Increased Stopping Power: The larger wound channels created by hollow points can incapacitate a threat more quickly, which is a critical factor in defensive shooting.

Why You Should Buy Hollow Point Bullets

Hollow point bullets are crucial for defensive and self-defense scenarios where the primary objective is to neutralize a threat efficiently and rapidly. In such situations, the goal is to incapacitate an aggressor swiftly to prevent harm to oneself or others. While terminal ballistics, the study of a projectile's behavior and effects after impacting a target, can be a grim topic, it's essential that bullets carried for defensive purposes cause significant disruption within the target to quickly stop any unlawful force being used against you or another. Another important considerationis that hollow point projectiles are less likely to over-penetrate, thus reducing the risk of the projectile leaving its intended target and striking an unintended target.

Glock 43 with jacketed hollow points (JHP)

Jacketed Hollow Point (JHP) rounds increase the probability of stopping a threat more quickly than Full Metal Jacket (FMJ) rounds while decreasing the possibility of over-penetration.

Conclusion

Hollow point bullets are a critical development in ammunition technology, offering enhanced stopping power, reduced risk of over-penetration, and improved energy transfer. Whether used by law enforcement, for personal defense, or for hunting, hollow points and their variations like JHPs provide shooters with effective options tailored to their specific needs and situations. Understanding the different types of hollow points available can help shooters choose the right ammunition for their firearm and their shooting objectives, ensuring optimal performance and safety.