The .M16 is a military rifle that was first introduced in the 1960s. It is known for its lightweight design and high rate of fire, making it effective in combat situations. The rifle uses a 5.56x45mm NATO cartridge, which allows for greater accuracy and reduced recoil compared to larger caliber weapons. The .M16 has undergone several modifications over the years, leading to various models, including the M16A1, M16A2, and M16A4. It has been widely used by the United States Armed Forces and many other military organizations around the world, becoming a symbol of modern infantry warfare.