Which of the following is a common cause of a failure to eject?

A worn extractor is a common cause of a failure to eject because the extractor is the component responsible for grabbing the cartridge case after it has been fired. If the extractor is worn, it may not be able to hold onto the case firmly enough to pull it from the chamber. This can lead to situations where the spent case fails to be ejected properly, resulting in a malfunction. A properly functioning extractor is crucial for reliable cycling in semi-automatic and automatic firearms, as it ensures that each spent cartridge is effectively removed from the chamber, allowing for the chambering of the next round.

While other factors like incorrect ammunition, dry firing, or a wet environment can contribute to feeding and cycling issues, they do not directly impact the extractor's mechanical function in the same way that a worn extractor does. Thus, understanding the role of the extractor and its condition is essential for diagnosing failures to eject.