Fact Check: Are Full Metal Jacket (FMJ) bullets considered armor-piercing?

Are Full Metal Jacket (FMJ) Bullets Considered Armor-Piercing?

Introduction

The claim in question is whether full metal jacket (FMJ) bullets are considered armor-piercing. This question arises from the varying definitions and classifications of ammunition types, particularly in relation to their intended use and effectiveness against body armor. Understanding the distinctions between FMJ and armor-piercing (AP) ammunition is crucial to addressing this claim.

What We Know

Definition of FMJ Bullets: FMJ bullets consist of a soft core, typically made of lead, encased in a harder metal jacket, which can include materials like copper or steel. This design is primarily intended to enhance the bullet's performance in terms of velocity and accuracy while reducing barrel fouling 2 4.
Definition of Armor-Piercing Bullets: Armor-piercing ammunition is specifically designed to penetrate armor. These bullets often have a hardened core made from materials such as steel or tungsten, which allows them to defeat protective barriers that standard FMJ rounds cannot 1 3 5.
Performance Against Armor: While some FMJ rounds may penetrate certain types of body armor under specific conditions, they are not designed for this purpose. The effectiveness of FMJ against armor is largely dependent on the type of armor and the caliber of the bullet 4 6.
Legal and Regulatory Definitions: In some jurisdictions, the legal definition of armor-piercing ammunition may include specific criteria that FMJ bullets do not meet. For example, the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) has regulations that distinguish between different types of ammunition based on their design and intended use 5.

Analysis

Source Evaluation

Wikipedia: The entries on FMJ and armor-piercing ammunition provide a general overview and are useful for basic definitions. However, Wikipedia is a user-edited platform and may not always reflect the most current or comprehensive information 2 3.
TheGunZone: This source offers a clear distinction between FMJ and armor-piercing ammunition, emphasizing that FMJ is not specifically designed to penetrate armor. However, it is important to consider that TheGunZone may have a bias towards promoting safe and responsible firearm use, which could influence its presentation of information 4 5 6.
National Institute of Justice: This source is a government entity that provides training and resources related to firearms examination. Its information is likely to be reliable, but it may focus more on the technical aspects of ammunition rather than public understanding 1.
BulletSafe: This blog discusses the use of FMJ in relation to body armor and provides insights into the performance of different ammunition types. While it offers practical information, it is essential to consider the potential for bias, as the site promotes bulletproof vests and related products 10.

Methodology and Evidence

The claims regarding FMJ and armor-piercing ammunition rely on definitions and practical performance. The distinction between the two types of ammunition is based on their design and intended use, which is supported by various sources. However, the effectiveness of FMJ against armor can vary based on factors such as bullet caliber and armor type, which complicates the assessment of their armor-piercing capabilities.

Conflicting Information

Some sources suggest that FMJ can penetrate certain types of armor, while others firmly state that FMJ is not armor-piercing. This discrepancy highlights the need for more precise definitions and a better understanding of the context in which these bullets are used.

Conclusion

Verdict: False

The claim that full metal jacket (FMJ) bullets are considered armor-piercing is false. The evidence indicates that FMJ bullets are not specifically designed to penetrate armor, which is the defining characteristic of armor-piercing ammunition. While FMJ rounds may occasionally penetrate certain types of body armor under specific conditions, this is not their intended purpose, and they do not meet the legal definitions of armor-piercing ammunition in many jurisdictions.

It is important to note that the effectiveness of FMJ against armor can vary based on factors such as bullet caliber and the type of armor being used. This variability adds complexity to the discussion but does not change the fundamental distinction between FMJ and armor-piercing ammunition.

Moreover, while the sources consulted provide a range of information, there are limitations in the available evidence, particularly regarding the performance of FMJ against different armor types. Readers are encouraged to critically evaluate information and consider the context in which ammunition is discussed, as definitions and regulations can vary significantly.

Sources

National Institute of Justice. "Firearms Examiner Training." NIJ
Wikipedia. "Full metal jacket (ammunition)." Wikipedia
Wikipedia. "Armour-piercing ammunition." Wikipedia
TheGunZone. "Is full metal jacket ammo armor-piercing?" TheGunZone
TheGunZone. "What is considered armor-piercing ammo?" TheGunZone
TheGunZone. "Is FMJ ammo armor-piercing? | [April Updated]." TheGunZone
RMA Defense. "Body Armor Ammunition Guide." RMA Defense
ShunVogue. "Are Full Metal Jacket Bullets Armor Piercing?" ShunVogue
Prepare and Protect. "Bullet Types: A Reference Guide." Prepare and Protect
BulletSafe. "The Truth About FMJ Rounds, Defensive Handgun Use, and Body Armor." BulletSafe