Hollow Point vs. Full Metal Jacket (FMJ) Ammo: Understanding the Key Differences

When it comes to ammunition selection, few debates are as common as the choice between Hollow Point (HP) and Full Metal Jacket (FMJ) rounds. 

Credit: Althom

Whether you're a seasoned gun owner, a concealed carry permit holder, or just getting into firearms, understanding the differences between these two types of ammo is essential for making the right choice. 

In this guide, we’ll break down everything you need to know about HP and FMJ ammunition, including their uses, effectiveness, legality, and costs.

What is Full Metal Jacket (FMJ) Ammo?

Full Metal Jacket (FMJ) ammunition consists of a soft lead core encased in a harder metal shell, usually made of copper or another alloy. FMJ rounds are designed to maintain their shape upon impact, allowing them to penetrate targets effectively without expanding or deforming significantly.

How It Works:

• Penetration: The metal jacket prevents deformation, allowing the bullet to pierce through barriers and retain momentum.
• Consistent Performance: Reliable feeding in semi-automatic firearms, making FMJ a go-to for training.

Pros of FMJ Ammo:

• Reliable Feeding: FMJ bullets have a smooth, round profile that helps prevent feeding issues in semi-automatic firearms.
• Cost-Effective: FMJ rounds are generally cheaper than hollow points, making them a popular choice for target shooting and training.
• Deep Penetration: Because they do not expand upon impact, FMJ rounds can penetrate deeply, making them effective against barriers and protective materials.
• Legal in More Jurisdictions: Some areas restrict hollow points, making FMJ the only available option.

Cons of FMJ Ammo:

• Over-Penetration Risk: FMJ bullets can pass through a target and continue traveling, increasing the risk of collateral damage in self-defense situations.
• Less Stopping Power: Because they do not expand, FMJ rounds transfer less energy into the target, potentially requiring multiple shots to stop a threat.

What is Hollow Point (HP) Ammo?

Hollow point bullets are easily recognizable by the hollow cavity at their tip. This design isn’t just for show—it serves a critical purpose. When a hollow point strikes a target, the cavity forces the bullet to expand, creating a larger wound channel and transferring energy more efficiently.

How It Works:

• Expansion: Upon impact, the hollow cavity causes the bullet to “mushroom,” increasing its diameter. This expansion slows the bullet, reducing over-penetration risk.
• Energy Transfer: By expanding, the bullet dumps more energy into the target, maximizing stopping power.

Pros of Hollow Point Ammo:

• Superior Stopping Power: HP bullets expand upon impact, transferring more kinetic energy into the target and stopping threats more effectively.
• Reduced Over-Penetration: Because they expand and slow down upon impact, hollow points are less likely to pass through a target and endanger bystanders.
• Better Terminal Performance: Expansion increases the wound cavity, making HP rounds more effective for self-defense and hunting.

Cons of Hollow Point Ammo:

• Higher Cost: HP rounds are generally more expensive than FMJ rounds due to the additional manufacturing complexity.
• Potential Legal Restrictions: Some jurisdictions, such as New Jersey, restrict or prohibit the civilian use of hollow-point ammunition.
• May Cause Feeding Issues: In some firearms, hollow points may not cycle as smoothly as FMJs, especially in older or poorly maintained guns.

Hollow Point vs. FMJ: When to Use Each Type

The choice between hollow point and full metal jacket ammunition depends on your intended use. Let’s look at common applications for each type:

Self-Defense

Winner: Hollow Point

• Stopping a threat quickly and effectively is the goal in a self-defense situation, and HP rounds excel at this by expanding and delivering maximum energy to the target.
• The reduced risk of over-penetration helps ensure that innocent bystanders are not endangered.

Target Practice & Training

Winner: FMJ

• Cost is a major factor when buying ammo in bulk, and FMJ rounds are much more affordable for regular practice sessions.
• Consistent performance and reliability make FMJ the preferred choice for range use.

Hunting

Winner: Hollow Point

• For hunting medium to large game, HP bullets create larger wound channels and offer cleaner, more ethical kills.
• Expansion helps prevent over-penetration, ensuring the bullet stays within the target.

Military & Law Enforcement Use

Winner: Situational

• Military forces traditionally use FMJ rounds due to international treaties, such as the Hague Convention, which prohibit the use of expanding ammunition in war.
• Law enforcement agencies often prefer hollow points to minimize collateral damage and improve stopping power in urban environments.

Cost Comparison: Hollow Point vs. FMJ

Hollow points are generally more expensive than FMJ rounds. A standard box of 50 FMJ 9mm rounds may cost around $15-$20, whereas a box of 50 HP 9mm rounds can cost $25-$40, depending on the brand and bullet weight. 

 

For budget-conscious shooters, FMJ rounds are the go-to for training, while HP rounds are reserved for defensive carry and home protection.

Ballistic Performance and Energy Transfer

A key aspect of comparing FMJ vs. HP rounds is their ballistic performance:

• Velocity: FMJ rounds tend to maintain higher velocities, leading to deeper penetration.
• Expansion: Hollow points expand significantly, creating a larger wound cavity and more tissue damage.
• Energy Transfer: HP rounds transfer more kinetic energy upon impact, leading to quicker incapacitation of a target.

Effectiveness Against Barriers

Different ammunition types perform differently against common barriers:

• FMJ: Performs well against wood, drywall, and metal but often over-penetrates soft targets.
• HP: Performs well against soft targets but may struggle against hard barriers or glass.

Legality Considerations

While FMJ rounds are widely accepted and legal almost everywhere, hollow points face restrictions in some states and countries. Always check your local laws before purchasing or carrying hollow-point ammunition to ensure compliance with regulations.

Best Brands for FMJ and HP Ammo

Some of the most reputable manufacturers of FMJ and HP rounds include:

• Federal Premium
• Hornady
• Winchester
• Speer Gold Dot
• Remington
• Sig Sauer

Comparison Table: Hollow Point vs. FMJ

Final Thoughts: Which One Should You Choose?

Choosing between hollow point and FMJ ammo isn’t about finding a “winner”—it’s about matching the bullet to the task. Hollow points excel in self-defense by prioritizing stopping power and safety, while FMJ’s affordability and penetration make it ideal for training and specific tactical uses.

• For self-defense: Hollow points are the best choice due to their superior stopping power and reduced risk of over-penetration.
• For range practice and target shooting: FMJ is the economical and practical option.
• For hunting: Hollow points provide better performance and humane kills.
• For legal compliance: Check local regulations, as some areas restrict hollow-point ammunition.

Understanding the key differences between FMJ and HP ammunition helps you make informed decisions based on your shooting goals. Whether you're stocking up for practice, self-defense, or hunting, selecting the right ammo is crucial for optimal performance and safety.