Which of the following is NOT a pre-fire safety check for the 81mm mortar?

The correct answer, which identifies a statement that is not a pre-fire safety check for the 81mm mortar, relates to the positioning of the firing pin recess. While ensuring that the firing pin recess is oriented appropriately is crucial for proper function and safety during handling, the specific direction it faces (downwards or otherwise) is not conventionally included as a primary step in the pre-fire safety checks.

The pre-fire safety checks generally focus on the structural integrity and security of the mortar components. For instance, confirming that the cannon is locked to the baseplate ensures that the assembly is stable and secure during firing, which prevents accidental disassembly. Similarly, ensuring that the bipod locking latch is secured is essential to maintain the integrity of the setup during operation, reducing the risk of malfunction or accident. Additionally, checking for mask and overhead clearance is vital for ensuring the safety of both personnel and equipment from potential hazards, such as obstacles that could interfere with the firing trajectory or endanger nearby individuals.

Thus, while all checks are important, the orientation of the firing pin recess specifically does not fit into the standard list of pre-fire safety checks in the context given.