What general mechanical failure does bolt override indicate?

Bolt override indicates a specific mechanical failure where the bolt fails to fully close and secure a round in the chamber, which can occur when a round is not properly chambered. In this failure mode, the bolt's locking lugs are unable to engage with the corresponding surfaces in the receiver, leading to a situation where the bolt is either partially or completely off the round that is intended to be fired. This disruption affects the cycling of the firearm, resulting in the inability to fire or feed the round appropriately.

Understanding bolt override is crucial because it highlights the importance of proper ammunition handling and the correct functioning of the chamber. Appropriate chambering ensures that the cartridge is seated correctly and allows for reliable operation. In this context, recognizing that improper chambering is the underlying cause of bolt override helps in troubleshooting and effectively addressing the issue at hand. The other choices describe different types of mechanical failures that do not correlate directly with the specific symptom of bolt override.