Firearm maintenance is a periodic preventive maintenance procedure to ensure the proper function of a firearm. Typically firearm maintenance is performed by the owner of the firearm using simple methods such as cleaning the firearm with gun oils, and lubricating with similar oils and greases. When a firearm presents with physical damage related to the ordinary use of the firearm, or when a firearm malfunctions in a life-threatening manner a professional gunsmith should perform advanced maintenance to determine if the firearm is repairable and/or safe to shoot.
The consequences of neglecting such maintenance can be serious. For instance, during the Vietnam War, the M-16 rifle was distributed to US troops with literature from Colt Firearms claiming that the weapon was self-cleaning, which implied to many to mean that it did not have to be maintained. However, this attitude compounded the rifle's design flaws to make the weapon notorious for repeated failures in combat, which led to needless casualties among US forces. Once the problem was acknowledged by the US military, the weapon was not only subject to upgrades, but US troops were also trained in proper maintenance of the weapon and supplied with cleaning kits and an illustrated pamphlet on the subject by Will Eisner.
The ordinary action of a firearm releases fine particles of gunpowder, metals, and other contaminates into the inner-space of a firearm, which may cause malfunctions, or in rarer cases of extreme buildup may cause the firearm to explode upon being fired. It has been widely reported that firearms without a spring to control the inertia of the firing pin require constant cleaning of the bolt assembly; as extremely dangerous phenomena such as slamfire may occur. Slamfire is a malfunction in which a firearm which is normally semi-automatic may temporarily and involuntarily become fully automatic, firing repeatedly—without another pull of the trigger—until the firearm is out of ammunition.
Every major firearms manufacturer provides detailed information on the proper methods used to disassemble, clean, and reassemble a firearm they produce. This information is usually packaged with the firearm. In the event that this information is not present with the firearm at the point of purchase, it is advisable to ask the manufacturer where this information may be obtained. For safety reasons the manufacturer's directions for cleaning, maintenance, and care should always be followed.