Ambidextrous bolts that allow a user to quickly and easily change the side of the firearm from which a spent casing is ejected by application of a simple switching mechanism that does not require disassembly of the firearm. Aspects of the disclosure also include debris shields for improving the longevity and reliability of extractors, firearms that are configured for ambidextrous operation, methods of using firearms, and methods of modifying firearms to incorporate ambidextrous functionality.