Full Metal Jacket (FMJ) bullets are rounds that are designed for target practice, training, and shooters who want penetration without expansion. The jacket is a metal casing that covers the lead core of the bullet. This makes the FMJ more resistant to deformation than a traditional lead bullet and thus will penetrate deeper into a target.
There are two main types of FMJ ammunition: ball and flat-nosed. Ball ammo is typically used in handguns because it provides better accuracy due to its round shape. Flat-nosed ammo is often used in rifles because it provides more stopping power and penetration.
FMJ ammo has several benefits over traditional lead bullets. It is more accurate due to its round shape, and it can penetrate deeper into a target because of the jacket. However, FMJ ammo also has some drawbacks. It is more expensive than traditional lead ammo, and it can cause more damage to targets than lead bullets.