Which cycle of operation occurs after a round is fired and the recoil causes the barrel and slide to move rearward in the M9 pistol?

After a round is fired from the M9 pistol, the recoil energy generated by the explosion of the gunpowder causes the barrel and slide to move rearward. This movement initiates the unlocking cycle of operation. During unlocking, the barrel and slide separate; the barrel pivots down, allowing the locking lugs to disengage from the slide.

This phase is crucial because it allows the slide to move rearward, which is necessary for the subsequent operations of extraction and ejection of the spent casing. The unlocking cycle is essential in ensuring that the firearm functions correctly and can prepare for the next shot by manipulating the components effectively.

In contrast, the other cycles such as feeding, extraction, and ejection occur after the unlocking cycle. Feeding involves the process of bringing a new round into the chamber, extraction refers to the pulling of the spent casing from the chamber, and ejection is the expulsion of that spent casing from the firearm. Each step is interconnected, but they must follow the unlocking phase to maintain proper operational sequence.