Which part is NOT likely to cause problems with firing pin operation in a pump action shotgun?

The operating rod is a component that primarily functions to cycle the action of the shotgun, allowing the shooter to chamber a new round after firing. Its purpose is more about the movement of the ammunition than the actual ignition of the cartridge. Therefore, issues with the operating rod are not typically linked to the performance of the firing pin, which is responsible for striking the primer of the shell to initiate the firing sequence.

In contrast, other components such as the bolt channel, locking lug, and trigger spring have a more direct correlation with the firing pin's operation. The bolt channel can affect the bolt's ability to move properly, which can influence the firing pin's alignment and function. The locking lug plays a critical role in securing the bolt in place during firing, and if it is not functioning correctly, it could affect the firing sequence. Finally, the trigger spring is essential for the proper engagement and disengagement of the trigger mechanism, which directly impacts whether the firing pin can be released effectively when the trigger is pulled.