What is the standard round for the M4 series weapon?

The M4 series weapon is designed to use the M855 Ball round as its standard ammunition. The M855 is a 5.56mm cartridge that features a steel penetrator as part of its projectile, which enhances its ability to penetrate soft targets and barrier materials while still maintaining a relatively low recoil.

The M855 round is specifically engineered to take advantage of the M4’s characteristics, providing a balance between accuracy, range, and lethality. It is optimized for use in both close quarters and longer-range engagements, making it versatile for various combat scenarios.

In contrast, the other types of rounds listed, like M193 Ball, are less commonly used in the M4 platform today due to differences in ballistics and performance characteristics. The 5.56mm Frangible rounds are designed for specific environments to minimize risks of ricochet and over-penetration, while the 7.62mm NATO is a completely different cartridge meant for larger caliber platforms, such as the M14 or sniper rifles, and does not match the M4's design specifications. Thus, the M855 Ball is the standard round, ensuring optimal performance for the M4 series weapon.