Copper vaporization in the bore is classified as an issue related to which kind of finish?

Copper vaporization in the bore is primarily associated with a rough finish. A rough finish can create more friction and heat during the firing process due to the increased surface area, which contributes to the vaporization of copper from the bullet. This occurs as the rough texture can lead to greater wear on the barrel's interior and facilitate higher temperatures, resulting in the copper from the projectile melting and vaporizing, which can lead to fouling and accuracy issues over time.

In contrast, a high finish or polished finish typically results in a smoother bore, reducing friction and heat buildup, which minimizes the risk of copper vaporization. Therefore, recognizing the relationship between barrel finishes and the behavior of materials under high-stress conditions is crucial in understanding performance and maintenance in firearms.