The 5.56mm NATO is a military cartridge developed in the 1960s, primarily used by NATO forces. It is known for its lightweight design and high velocity, making it effective for infantry rifles. The cartridge is often chambered in firearms like the M16 and M4 rifles, providing soldiers with improved accuracy and reduced recoil. This caliber is designed for use in various environments and is effective at ranges up to 500 meters. The 5.56mm NATO has become a standard for many armed forces around the world, contributing to its widespread adoption in military operations.