What is the caliber of the M16/A2 rifle?

The M16/A2 rifle is specifically designed to fire a 5.56 mm cartridge, which is a standard NATO caliber. This caliber is known for its high velocity and relatively low recoil, making it suitable for a variety of military applications. The 5.56 mm round allows for effective engagement of targets at a range while also maintaining manageable handling characteristics for the operator.

The designation of the 5.56 mm cartridge is part of a larger metric system, while the .223 caliber is often used interchangeably in civilian contexts. However, the military specification of the rifle's cartridge is technically 5.56 mm, making it crucial for understanding its capabilities and characteristics. Thus, the correct choice reflects the accurate military designation for the M16/A2 rifle’s caliber.