What is the maximum range of the M203?

The M203 is a single-shot, breech-loaded, pump-action grenade launcher designed to be mounted underneath the barrel of an M16 or M4 series rifle. Its maximum effective range is indeed approximately 400 meters when targeting personnel. This range is suitable for engaging enemies accurately while also accounting for the projectile's trajectory and the intended use for indirect fire.

While the other options indicate longer ranges, the 400-meter maximum effectively reflects the operational capabilities of the M203 when aimed at a specific target. Engaging targets beyond this distance often falls outside its design parameters, leading to decreased accuracy and effectiveness. The shorter range allows for more precision in combat situations, particularly in environments where collateral damage must be minimized, such as urban settings.