What type of ammunition is primarily used by the M16A3/M4A1 service rifle?

The M16A3 and M4A1 service rifles primarily utilize ball ammunition, which is a type of projectile designed for general-purpose use in military applications. Ball ammunition is characterized by its solid metal bullet and consistent performance, making it suitable for a wide range of combat situations. This type of ammunition is effective for delivering lethal force at various ranges, appropriate for the engagement scenarios that service members may face.

In contrast, tracer ammunition is designed with a pyrotechnic composition at the base of the bullet, allowing for visibility of the projectile's trajectory, which can be useful for signaling and adjusting fire but is not the primary choice for standard engagements. Blank ammunition is used for training purposes, simulating the firing experience without the projectile, while dummy rounds are inert cartridges used to provide training in the handling and operation of the rifle without any risk of discharge. The primary purpose of the M16A3 and M4A1 in combat necessitates the use of ball ammunition to ensure effectiveness and reliability in firing scenarios.