What is the term for initiating the primer detonation of the cartridge?

The term for initiating the primer detonation of the cartridge is "firing." In this context, firing refers to the action that sets off the primer, which in turn ignites the propellant within the cartridge, leading to the discharge of the projectile. This action is a critical aspect of the functioning of firearms, as it is the moment when the energy stored in the cartridge is released for propulsion.

The other terms do not accurately describe this specific action. "Unlocking" typically refers to the process of disengaging a firearm's mechanisms to allow for the cycling of the action after firing. "Cocking" involves placing the firing mechanism in a ready state for firing, often by pulling back a hammer or striker. "Feeding" denotes the action of loading a cartridge into the chamber, preparing it for firing, but it does not relate to the actual ignition of the cartridge. Understanding these distinctions is vital for clear comprehension of firearm operations and terminology.