What could be the most likely cause of a misfire even if a primer is struck correctly?

The most likely cause of a misfire, even when the primer is struck correctly, is faulty ammunition quality. Misfires can occur due to several factors inherent to the ammunition itself, such as defective primers, inconsistent powder charges, or improperly manufactured brass. If the quality of the ammunition is subpar, even a correctly struck primer may not ignite the propellant, leading to a failure to fire.

While considerations regarding firing pin engagement, storage conditions, and lubrication are important in firearm maintenance and operation, they are less directly related to the specific scenario of misfires associated with defective ammunition. Quality control in ammunition manufacturing is crucial; any failure in these processes can result in misfires despite proper handling and operation of the firearm. Thus, focusing on ammunition quality highlights a key area of inspection when diagnosing misfires.