Which action is performed when the slide moves rearward?

When the slide moves rearward, it primarily performs the action of cocking the hammer in the context of the M9 Service Pistol. As the slide cycles backward during the firing sequence, it engages the internal mechanisms of the firearm that allow the hammer to be cocked. This is essential for the subsequent firing action, as the cocked hammer is what ultimately strikes the firing pin upon release, igniting the cartridge.

The movement of the slide serves multiple functions in the cycle of operation for semi-automatic pistols; however, the specific question regarding the action associated with the rearward movement aligns with the cocking of the hammer. Understanding this is important for grasping the fundamental mechanics of how the M9 operates during the firing cycle.