Barrel corrosion is the chemical deterioration of a barrel bore and/or chamber surface.

A common cause of barrel corrosion is the use of ammunition with corrosive primers and/or powder and then not being properly cleaned.

Footnotes / Sources:

“Glossary ⇒.” Sporting Arms and Ammunition Manufacturers’ Institute. Ed. SAAMI’s Technical Committee. Web. 15-18 Jan. 2011.