When does the long recoil feeding step occur?

The long recoil feeding step occurs when the firearm's action operates in a mechanism that allows the bolt and barrel to recoil together before separating to load a new cartridge. This process typically does not relate directly to the phases of initial chambering, firing, or ejection as suggested in the other options.

During the initial chambering, the firearm loads a round into the chamber, which is a separate action from the recoil process. Just before firing, the firearm is ready to discharge, but the long recoil mechanism has already performed its function by preparing the chamber for the next shot. After ejection, the spent cartridge case is expelled, and the firearm is ready to chamber another round, yet this still does not directly tie into the long recoil feeding step.

Since the long recoil feeding is specific to the operation of loading a new cartridge following the recoil cycle and is not accurately represented in the aforementioned scenarios, the most appropriate response is that it does not occur in any of the described options.