The M4 is a popular military rifle used by the United States Armed Forces and many other countries. It is a gas-operated, air-cooled, magazine-fed carbine that fires 5.56×45mm NATO ammunition. The M4 is known for its versatility, lightweight design, and modularity, allowing soldiers to customize it with various attachments like scopes and grenade launchers. Originally developed in the 1990s, the M4 is an evolution of the earlier M16 rifle. It has become the standard issue for infantry troops, replacing the M16 in many roles. The M4's effective range is approximately 500 meters, making it suitable for various combat situations.