The term fouling typically refers to any situation where an object or outside elements have impeded the function of a firearm. Fouling can happen when dirt or debris enters the chamber and resists the internal movement of components preventing a round from being chambered or a spent case from being extracted and ejected. Fouling can also inhibit the seating of a magazine or the proper loading of a semi-automatic firearm. The most dangerous type of fouling is when an object or debris is partially or completely obstructing the barrel. This can cause a catastrophic failure of the firearm and severe injury to the shooter.