01Oct06 Today, at an Urban Shotgun Program in MA, a Mossburg 590, being used by a student suddenly went down. Normally, the Mossburg is among the most reliable of all the shotguns we see, but, on this copy, the magazine follower got stuck in the forward portion of the magazine tube, and spring pressure in the tube naturally went dead. The gun was immediately out of action, and my student was unable to complete the exercise. We tried to free the follower, without success. It was wedged tight in the tube. My student was compelled to switch to another shotgun in order to finish the Course. I subsequently learned that the magazine follower responsible for all this heartburn was not the one that came with the gun! The factory follower had been replaced with an aftermarket substitute. Unfortunately, after replacing the factory part, the gun was never tested, until it found its way to our Program! My student learned a frustrating, but important, lesson. Most aftermarket parts are inferior to the factory parts they are designed to replace. However, there are exceptions. In any event, any time a part is replaced in, or modification is made on, a serious gun, the gun must be thoroughly tested afterward, BEFORE being placed back into service! My student was lucky! This unexpected difficulty was detected during training, and the price he paid was only a moment or two of frustration, not a fatal injury. Undetected, it could easily have been the later! /John