The INERT 9mm FMJ (Full Metal Jacket) Luger round is a non-functional replica or inert version of the standard 9x19mm Parabellum cartridge commonly used in handguns.

Here's a breakdown:

1. Caliber: The 9mm Luger, also known as 9x19mm Parabellum, is one of the most widely used pistol cartridges globally.

2. Projectile Type: The FMJ (Full Metal Jacket) projectile is a common type of bullet design where the lead core is encased in a harder metal, typically copper or steel. This design ensures better penetration and less deformation upon impact, making it suitable for target shooting and military applications.

3. Inert Nature: The term "inert" indicates that the round is not live or functional. It's typically used for training, display, or educational purposes. Inert rounds lack the primer, powder, and sometimes even the bullet, making them incapable of firing.

4. Purpose: Inert rounds are often used for training exercises where handling live ammunition would pose unnecessary risks. They are also used for educational purposes, allowing individuals to handle and study cartridges without the danger associated with live ammunition.

5. Identification: Inert rounds are usually clearly marked as such to prevent confusion with live ammunition. They may have markings indicating "inert," "dummy," or "training use only."