Which is the standard round used in the M16A2 and M4 series weapons and also linked and used in the M249?

The standard round used in the M16A2 and M4 series weapons, as well as linked for use in the M249, is the Cartridge, 5.56mm, ball, M855. This round is specifically designed for military applications and is optimized for use in both rifles and light machine guns, providing consistency and reliability across different platforms.

The M855 cartridge features a steel penetrator tip designed to enhance performance against a variety of materials, making it suitable for combat situations. Its compatibility with the M16A2 and M4 rifles ensures effective operation in terms of accuracy and lethality. Additionally, the same cartridge being used in the M249 allows for logistical simplicity, as soldiers can share ammunition across these different weapons systems.

Using a single type of round for multiple platforms aids in training and simplifies ammunition supply and management in the field, which are critical factors in military operations. The M855 round’s specifications and intended application align perfectly with the requirements of the M16A2, M4, and M249.