What action entails the removal of the expended cartridge case from the chamber?

The action that involves removing the expended cartridge case from the chamber is known as extracting. In the cycle of operation for a firearm, extracting refers specifically to the process where the extractor engages the rim of the spent cartridge case and pulls it out of the chamber after firing. This is a critical step in ensuring the firearm can continue to function properly, as it clears the chamber for the next round to be chambered and fired.

Ejecting typically follows extracting; it involves the case being expelled from the firearm after it has been extracted. Locking refers to the mechanism that secures the bolt or breech in position to allow for the firing of the round, and feeding concerns the mechanism that brings a new round into the chamber from the magazine. The term extracting specifically highlights the action of removing the spent case, making it the correct choice in this context.