What happens to a bullet that is fired through a bore with excessive copper fouling?

When a bullet is fired through a bore with excessive copper fouling, it may cause wider shot spread. Copper fouling can affect the consistency of the bullet's flight path in several ways.

Firstly, fouling can alter the dimensions of the bore, making it inconsistent, which can impact the bullet's stability as it travels through the barrel. This variability can lead to decreased accuracy and greater dispersion of the bullet's trajectory, resulting in wider shot spread. Additionally, the copper buildup can increase friction between the bullet and the barrel, which can further contribute to alterations in velocity and stability.

In contrast, if the gun is well-maintained and free of fouling, the bullet's performance is more predictable, leading to tighter groupings and improved accuracy. Therefore, excessive fouling has clear negative implications for shot spread, making this the most accurate answer.