In meters, what is the maximum range of the M870 shotgun using "00" buck shot round?

The maximum effective range of the M870 shotgun when using "00" buckshot is generally recognized to be around 640 meters. This distance is based on the ballistic characteristics of the "00" buckshot, which consists of multiple pellets designed to deliver a significant amount of energy upon impact while providing a broad spread pattern.

At this range, the shotgun remains effective in delivering incapacitating fire, though accuracy and precision are influenced by various factors such as spread and environmental conditions. While the ranges listed in the other options are higher, they surpass the reliable effectiveness of the M870 shotgun with "00" buckshot, where performance and stopping power begin to decline due to loss of velocity and increased pellet spread over distance.