Jams. Some of the guys have problems with the new cheap shells with the base ripping when the gun tries to eject. But I think that's with the autos, not sure. Pumps - just about every problem with ejection is operated error - short stroking. We shoot a " pump gun Friday " at the club on SCs. A lot of guys bought pumps, usually 870s. About 50% have a problem some time or another with short stroking because they're trying to shoot too fast. Well used guns can have mechanical problems but we don't see it very often, and not with new guns. An 870 has two arms going back to the bolt, so there isn't a whole lot than can go wrong. The Wingmaster is a well designed, well made gun. Always has been. The same for the Express, just not as pretty.