Final answer:
The action not part of the counter recoil phase is ejection. The counter recoil phase includes barrel unlocking, cocking, and extraction, but ejection occurs after this phase in the cycle of a firearm's operation.
Step-by-step explanation:
The action that is not part of the counter recoil phase is d) Ejection. During the counter recoil phase, the actions that typically occur are the barrel unlocking, the cocking of the firing mechanism, and the extraction of the spent cartridge or casing. Ejection is the action wherein the extracted casing is thrown out of the firearm, usually occuring after the counter recoil phase as part of the cycle of operation in a firearm.
Understanding the counter recoil phase can be related to Newton's third law of motion, which states that for every action there is an equal and opposite reaction. For example, when a gun is fired, the bullet is pushed forward and the gun is pushed backward. This explanation helps in grasping why ejection, which is the expulsion of the spent casing out of the firearm, is not considered as part of the counter recoil phase, but as a separate subsequent action.