Distinguishing TMJ Ammo from FMJ Ammo

Total metal jacket (TMJ) ammo and Full Metal Jacket (FMJ) ammo might have a thin difference. Some ammo fans are not even aware of the difference between the two. It is said that one cannot be called a pure expert on weapons if one cannot differentiate these two.

Key Takeaways

• TMJ completely covers the lead core of the bullet, usually used indoors to reduce lead content in the air.
• FMJ has a casing formed around the base core, usually made of solid materials like copper-nickel, brass, or steel alloy, and is preferable for gas-operated weapons due to lead deposits.
• TMJ and FMJ differ in penetration, price range, and material composition.

TMJ is a design in which it covers the lead core of the bullet completely. It is basically made up of brass or copper and is usually used indoors to cut the lead content in the air. Originally, this was created as a low-cost option to make a jacketed bullet. Most indoor shooting ranges recommend using this type of bullet during practice.

FMJ is an ammo that has a casing formed around the base core. Other samples have a hollow opening with lead exposed in the core. Its jacket is usually made up of solid material such as copper-nickel, brass, or steel alloy. It is also noted that this is preferable to be used in gas-operated weapons due to the lead deposits that it has.

The difference between TMJ and FMJ lies in their penetration and price range. Since TMJ is considered plated bullets, it has been observed that its penetration with hard targets is not as efficient as using an FMJ since the plating is more fragile and will likely fragment more compared to the full metal jacket. It is also believed that TMJ, due to its thin plating, has a limited capacity to be pressured in high velocities, not to mention that it is more expensive than the full metal jacket type.

It has been debated that TMJ is safer compared to FMJ concerning airborne lead. Some say otherwise, but in terms of shooting, it will all boil down to the kind of activity being done, be it an actual operation or simply practicing.