Which of the following is NOT a reason why your rifle might fail to fire?

A rifle may fail to fire for a variety of reasons related to ammunition, setup, and mechanical integrity. The correct choice indicates that excessive lubrication is not typically a reason for failure to fire. While proper lubrication is essential for the functioning of a firearm to ensure parts move smoothly, excessive lubrication is unlikely to directly prevent the firing mechanism from operating. Instead, it may cause issues such as attracting dirt or debris, which could lead to malfunctions over time, but it doesn't directly impede the firing process.

In contrast, factors like defective ammunition, improper setup, and a broken firing pin are more directly linked to failure to fire. Defective ammunition can simply fail to ignite or may not chamber properly, causing immediate failure. An improper setup could include issues such as incorrect sights, misalignment, or failure to properly load the firearm, which can contribute to firing problems. A broken firing pin would also directly prevent the weapon from striking the primer of the cartridge, making firing impossible. Therefore, the absence of failure due to excessive lubrication supports the assertion that it is not an inherent reason for a rifle to fail to fire.