Which cycle of operation of the M9 pistol occurs as the slide moves forward, stripping a round from the top of the magazine?

The cycle of operation that occurs as the slide moves forward, stripping a round from the top of the magazine is known as feeding. During this step, the slide of the M9 pistol engages with the magazine to pull a cartridge into the chamber. This is a crucial phase in ensuring that a round is properly positioned to be fired.

The process of feeding is directly linked to the magazine's design and the interaction between the slide and the rounds within it. When the slide recoils back and then moves forward again, its forward momentum is responsible for removing the top cartridge from the magazine and guiding it into the chamber.

Other options highlight different phases of the operation. Locking involves the mechanism that secures the slide in place when the gun is ready to fire, while ejecting pertains to the removal of a spent cartridge case after firing. Chambering refers specifically to the action of placing a round into the chamber but does not encompass the broader context of the entire feeding process. Therefore, identifying feeding as the expected operation when the slide moves forward clarifies the proper sequence of events in the functioning of the M9 pistol.