What is FMJ (Full Metal Jacket) Ammo?

At KIR Ammo we get a lot of questions in regards to ammunition types and uses.  Questions we get quite often are around Full Metal Jacket (FMJ) Ammunition and benefits/drawbacks with this type of bullet.

FMJ stands for Full Metal Jacket, which is a type of ammunition commonly used in firearms. FMJ bullets are typically made of lead, which is then encased in a copper or brass jacket that covers the entire bullet. This jacket helps to protect the bullet from damage as it travels through the barrel of the firearm and helps it maintain its shape during impact with a target.  Each manufacturer has a different approach and proprietary methods for creating full metal jacket bullets.

Some of the common types of full metal jacket bullets are:

  • Full metal jacket boat tail
  • Full metal jacket flat nose
  • Full metal jacket truncated cone

FMJ ammunition is often used for target shooting and training, as well as in military and law enforcement operations. It is also commonly used for hunting small game and varmints. One of the advantages of FMJ ammo is that it tends to be less expensive than other types of ammunition, which makes it a popular choice for those who shoot frequently. However, FMJ ammunition is not always the best choice for self-defense or hunting larger game, as it is less effective at causing terminal damage than other types of bullets such as hollow point or soft point bullets.

How Do I Identify FMJ Ammunition?

It’s pretty easy to tell if your ammo is FMJ. Full Metal Jacket (FMJ) ammunition is characterized by a bullet that is completely encased in a layer of metal, typically copper or a copper alloy, leaving only the base of the bullet exposed. This metal jacketing helps reduce barrel wear and improve feeding reliability in semi-automatic firearms. To determine if your ammunition is FMJ, you can follow these steps:

  • Visual inspection: Look at the tip of the bullet. FMJ bullets have a smooth, rounded, or pointed tip made of copper or a copper alloy, with no visible lead or hollow point. The metal jacket should be uniform and consistent in appearance, encircling the entire bullet except for the base.
  • Compare with other bullet types: Familiarize yourself with the appearance of other common bullet types, such as hollow points (HP), soft points (SP), or ballistic tips. These bullets will have visible cavities, exposed lead, or plastic tips, making them visually distinct from FMJ bullets.
  • Check the packaging or headstamp: The packaging of factory-loaded ammunition often provides information about the bullet type. Look for labels or descriptions such as “FMJ,” “Full Metal Jacket,” or “Metal Case.” In some cases, the headstamp (the markings on the base of the cartridge case) may also indicate the bullet type, although this is less common.

Consult the manufacturer’s specifications: If you are still unsure, you can refer to the manufacturer’s website or product documentation for specific information about the bullet type used in a particular brand or load of ammunition.

Advantages of a Full Metal Jacket Bullet:

  1. Penetration: FMJ bullets have excellent penetration capabilities due to their hard metal casing. This makes them a popular choice for shooting through obstacles like walls, barriers, or thick clothing.
  2. Reduced fouling: FMJ bullets tend to produce less fouling in the barrel of the firearm compared to other types of bullets. This is because the copper or brass jacket of the bullet helps to reduce the amount of lead residue left behind after firing.
  3. Cost-effective: FMJ bullets are often less expensive than other types of bullets, making them a popular choice for target shooting and training.
  4. Reliable feeding: FMJ bullets are known for their reliability in feeding and cycling through firearms. This is because their smooth metal casing allows them to slide easily into the chamber without getting caught or jammed.
  5. Consistency: FMJ bullets are manufactured to strict specifications, which means they tend to have consistent weights and dimensions. This can help improve accuracy and consistency in shooting.

Drawbacks of Full Metal Jacket Bullet:

  1. Limited stopping power: FMJ bullets are designed to penetrate, but they may not cause as much tissue damage as other types of bullets. This can limit their effectiveness for self-defense or hunting larger game.
  2. Overpenetration: Because FMJ bullets tend to penetrate deeply, they can pose a risk of overpenetration, which means the bullet may pass through the intended target and hit something or someone else.
  3. Ricochets: FMJ bullets can ricochet off hard surfaces, such as concrete or steel, which can create a danger for bystanders or unintended targets.
  4. Environmental concerns: FMJ bullets can leave lead deposits in the environment, which can be harmful to wildlife and the ecosystem. For this reason, some shooting ranges and hunting areas prohibit the use of FMJ bullets.
  5. Legal restrictions: In some jurisdictions, FMJ bullets are prohibited for certain types of hunting or self-defense purposes. It’s important to check local laws and regulations before using FMJ bullets.
  6. Poor terminal ballistics: FMJ bullets are not designed to expand upon impact with a target, which means they may not cause as much tissue damage as other types of bullets, such as hollow point or soft point bullets. This can limit their effectiveness for hunting or self-defense purposes.

Whether or not you choose to shoot FMJ ammunition in your guns, keep in mind the benefits and drawbacks of this type of ammunition.  We are always open to helping our customers choose the best ammo for their needs.  Contact us via e-mail or phone with any questions.  We would love to help you today!