An armorer, in the true sense of the word, is one who does more than just disassembles and assembles a firearm. He or she must know how each part in that particular firearm relates to the proper functioning of the weapon. Understanding what happens when the firearm is fired, unlocked, extracts, cocks, feeds, loads or chambers, and locks allows problems to be corrected before the weapon is used. Precluding problems may save the life of someone using a "Duty Gun"