A rough chamber in a lever or pump action firearm may cause which malfunction?

A rough chamber in a lever or pump-action firearm primarily affects the extraction of the spent cartridge case after firing. When a round is fired, the expansion of the brass case can create a tight fit against the chamber walls, particularly if those walls are rough or have inconsistencies. This can lead to a scenario where the case does not properly release from the chamber when the action is cycled, causing a failure to extract the spent case.

In this situation, the extractor, which is the component designed to grip the rim of the cartridge case and pull it out of the chamber, may not function effectively due to the increased friction. This can result in a jam, where the spent casing remains stuck while the action cycles, leading to the firearm being unable to load a new round or continue functioning until the malfunction is cleared.

The other potential malfunctions, while they can occur in different circumstances, are not primarily linked to the condition of the chamber. For instance, a failure to load typically arises from feeding issues, a failure to release can relate to components not properly disengaging, and a failure to fire is usually linked to problems with the firing mechanism or ammunition rather than chamber conditions. Thus, a rough chamber is most directly associated with the failure to extract.