The debate surrounding the stopping power of the 5.7x28mm and the 9x19mm (9mm Parabellum) cartridges is a long-standing one, fueled by passionate opinions and often conflicting anecdotal evidence. This article aims to provide a data-driven, nuanced comparison, moving beyond simplistic "which is better" narratives to explore the complexities of terminal ballistics and their implications for self-defense and law enforcement.
Understanding "Stopping Power"
Before diving into the specifics of each cartridge, it's crucial to define "stopping power." This term is often misused, conflating several distinct factors:
- Knockdown Power: This refers to the immediate incapacitation of a target, often associated with a dramatic fall. While visually impactful, knockdown power is unreliable and doesn't guarantee neutralization.
- Wound Ballistics: This encompasses the size, depth, and temporary cavity created by a projectile, directly impacting tissue damage and the likelihood of incapacitation.
- One-Shot Stop Rate: The percentage of engagements where a single shot results in immediate incapacitation. This is highly variable and influenced by numerous factors beyond the cartridge itself.
No single metric perfectly captures "stopping power," making direct comparisons challenging.
5.7x28mm: High Velocity, Small Caliber
The 5.7x28mm, popularized by the FN Five-seveN pistol, is a high-velocity, small-caliber cartridge designed to penetrate body armor. Its relatively light projectiles achieve high velocities, resulting in a significant temporary cavity upon impact. However, this also means a smaller permanent wound cavity compared to larger calibers.
Advantages of 5.7x28mm:
- High Velocity: Penetration through barriers and significant temporary cavity creation.
- High Capacity Magazines: Allows for carrying a large number of rounds.
- Reduced Recoil: Easier to control during rapid fire.
Disadvantages of 5.7x28mm:
- Smaller Caliber: Potentially less stopping power compared to larger calibers due to smaller permanent wound cavities.
- Over-Penetration: High velocity can lead to over-penetration, posing a risk to bystanders.
- Limited Availability of Ammunition: Compared to the 9mm, finding suitable ammunition might be more challenging in certain regions.
9x19mm: A Widely Used and Proven Caliber
The 9x19mm Parabellum, or simply 9mm, is one of the world's most widely used handgun cartridges. Its long history and widespread adoption have resulted in extensive testing and real-world data. Its heavier projectiles deliver substantial stopping power, especially with appropriate ammunition choices.
Advantages of 9x19mm:
- Larger Caliber: Generally produces larger permanent wound cavities compared to 5.7x28mm.
- Widely Available Ammunition: A vast selection of ammunition types is available, including various bullet designs optimized for different purposes.
- Proven Track Record: Decades of use in law enforcement and self-defense provide a substantial body of data.
Disadvantages of 9x19mm:
- Higher Recoil: Can be more challenging to control during rapid fire, especially for less experienced shooters.
- Lower Velocity: Compared to 5.7x28mm, penetration through barriers may be less effective.
The Verdict: Context Matters
There's no definitive "winner" in the 5.7x28mm vs. 9mm debate. The "better" cartridge depends heavily on the specific application and user factors. The 5.7x28mm's high velocity and penetration capabilities make it advantageous against threats wearing body armor, while the 9mm’s heavier projectiles generally offer better stopping power in typical civilian self-defense scenarios.
Ultimately, effective self-defense relies on factors far exceeding the choice of cartridge: proper training, shot placement, and situational awareness are paramount. The choice between 5.7x28mm and 9mm should be based on individual needs, experience, and a thorough understanding of their respective strengths and weaknesses. Consult with firearms experts and receive proper training before making a decision.
