During immediate action, if your bolt locks to the rear and either a round or casing is ejected, you should?

In the scenario where the bolt locks to the rear and a round or casing is ejected, it indicates a malfunction or a serious issue with the firearm that needs to be addressed properly. Turning the weapon over to maintenance personnel is the correct action because they are trained to diagnose and fix any problems with the firearm safely. This step ensures that the weapon is inspected and repaired to prevent further malfunctions during use.

Attempting to fire again or keep firing could lead to more significant issues, such as damaging the weapon or causing injury to the shooter or others nearby. Replacing ammunition immediately without further inspection also does not resolve the underlying problem that caused the bolt to lock. Therefore, ensuring the weapon is handled by qualified personnel maintains safety and reliability in the use of firearms.