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9MM Jacketed Hollow Point Ammunition Explained

by Daniel @HolsterCentral on December 06, 2023
9MM Jacketed Hollow Point Ammunition Explained

jhp cover 2

Introduction: 9mm Jacketed Hollow Point (JHP) ammunition is a popular choice for self-defense due to its design that aims to optimize stopping power while minimizing over-penetration. Understanding how it works, its benefits, and its pros and cons is crucial for responsible firearm ownership.

Design and Structure:

  1. Bullet Construction: A 9mm JHP bullet typically has a lead core surrounded by a jacket, usually made of copper. The front of the bullet features a hollow cavity.
  2. Hollow Point Cavity: The hollow point is a strategically designed opening at the bullet's tip. This cavity allows for controlled expansion upon impact.

9mm hollow point ammunition

How It Works:

  1. Expansion: Upon striking a target, the hollow point is designed to expand rapidly, creating a larger wound channel than non-expanding ammunition.
  2. Energy Transfer: The expansion maximizes energy transfer to the target, increasing the likelihood of incapacitating an assailant.
  3. Reduced Over-Penetration: Unlike Full Metal Jacket (FMJ) rounds, JHP ammunition is less prone to over-penetration. The expanded bullet is more likely to expend its energy within the target, reducing the risk of hitting bystanders or objects behind the target.


  1. Stopping Power: JHP bullets are designed to create larger wound channels, increasing the likelihood of stopping an assailant quickly.
  2. Reduced Over-Penetration: The design minimizes the risk of the bullet passing through the target and hitting unintended objects or people.
  3. Suitability for Self-Defense: The characteristics of JHP ammo make it a preferred choice for concealed carry and self-defense scenarios.


  1. Effective Stopping Power: JHP bullets are known for their effectiveness in quickly incapacitating a threat.
  2. Reduced Ricochets: The design reduces the likelihood of bullets bouncing off surfaces, enhancing safety in confined spaces.
  3. Wound Channel: The expanded bullet creates a larger wound channel, impacting the target's vital areas.


  1. Ammo Cost: JHP ammunition tends to be more expensive than FMJ rounds, impacting the cost of regular training sessions.
  2. Potential Feeding Issues: Some firearms may experience feeding issues with certain JHP designs. It's crucial to test different loads in your specific firearm for reliability.
  3. Limited Penetration: While reduced over-penetration is an advantage, in certain scenarios, JHP may be less effective against barriers like heavy clothing or glass.

Considerations for Use:

  1. Ammo Selection: Choose reputable JHP ammunition from established manufacturers, as consistency and performance can vary among brands.
  2. Training: While JHP is ideal for self-defense, it's recommended to practice with similar FMJ rounds to maintain proficiency without incurring excessive costs.
  3. Firearm Compatibility: Ensure your firearm reliably feeds and cycles with your chosen JHP ammunition through thorough testing.

jhp handgun ammunition

The history of JHP - 

The concept of jacketed hollow point ammunition has been attributed to several inventors and manufacturers, and its development is not attributed to a single individual or company. However, a notable early contributor to the development of hollow point ammunition is Douglas Wesson.

Douglas Wesson, along with his brother Joseph Wesson, co-founded Smith & Wesson, a renowned firearms manufacturer. In the early 20th century, around 1909, Douglas Wesson is credited with the design of the .38/44 Outdoorsman revolver, which was later known as the ".38/44 High-Velocity" model. This revolver was chambered for the .38 Special cartridge and featured a heavy frame to handle high-velocity loads.

The .38/44 High-Velocity ammunition for this revolver was among the early examples of jacketed hollow point ammunition. The bullets were jacketed soft points designed for higher velocity, and their hollow points contributed to controlled expansion upon impact.

While Douglas Wesson's work was influential, it's important to note that the development of hollow point ammunition involved contributions from various designers and manufacturers over time. The design has evolved to meet specific needs, especially in the context of self-defense, law enforcement, and other applications where controlled expansion and stopping power are crucial.


Flowering or Mushrooming with Hollow Points: Explained


Introduction: Flowering or mushrooming is a characteristic of hollow point (HP) bullets, specifically designed to enhance their terminal ballistics. This phenomenon occurs upon impact with a target and plays a crucial role in optimizing the bullet's effectiveness for various applications, particularly in self-defense.

Definition: Flowering or mushrooming refers to the expansion of the hollow point bullet upon contact with a target, resembling the shape of a flower or mushroom. The bullet, initially featuring a hollow cavity at its tip, deforms and expands, creating a larger diameter.

How It Occurs:

  1. Impact with Target: When a hollow point bullet strikes a target, the kinetic energy generated during impact forces the bullet's lead core to expand into the hollow cavity.
  2. Hydraulic Pressure: The fluid-like medium of the target (typically human tissue or ballistic gel) exerts hydraulic pressure on the bullet, causing controlled expansion.
  3. Controlled Deformation: The jacket, often made of copper, is designed to facilitate controlled deformation. The lead core expands outward, creating a "mushroom" shape.

Purpose and Design Objectives:

  1. Increased Stopping Power: Flowering enhances the bullet's stopping power by creating a larger wound channel. This is crucial for quickly incapacitating a threat.
  2. Energy Transfer: The expanded bullet transfers more kinetic energy to the target, improving the likelihood of disrupting vital organs and tissues.
  3. Reduced Over-Penetration: Flowering helps prevent over-penetration by ensuring that the bullet expends its energy within the target, minimizing the risk of hitting bystanders or objects behind the target.
  4. Optimized Terminal Ballistics: Hollow point ammunition is specifically designed for self-defense, where the goal is to neutralize a threat effectively and rapidly.

Benefits of Flowering or Mushrooming:

  1. Effective Wound Channel: The expanded bullet creates a larger wound channel, impacting vital areas and increasing the likelihood of incapacitating an assailant.
  2. Reduced Risk of Over-Penetration: Controlled expansion minimizes the risk of the bullet passing through the target and posing a danger to bystanders or property.
  3. Enhanced Energy Transfer: The mushrooming effect maximizes the transfer of kinetic energy, increasing the bullet's stopping power.


  1. Ammo Selection: Choosing reputable hollow point ammunition from established manufacturers is crucial to ensure consistent and reliable flowering.
  2. Firearm Compatibility: Testing different hollow point loads in your specific firearm is essential to ensure reliable feeding and cycling.
  3. Training: While hollow points are designed for self-defense, practicing with similar Full Metal Jacket (FMJ) rounds is recommended to maintain proficiency without excessive costs.

In conclusion, flowering or mushrooming is a deliberate design feature of hollow point bullets. It serves to optimize terminal ballistics, increase stopping power, and reduce the risk of over-penetration, making them well-suited for self-defense applications.


To learn more about defensive ammo, click here to read our defensive ammunition blog article




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