Decoppering is the act of removing

copper Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orang ...

and it is most commonly used in the context of the removal of copper residues from the

rifling Rifling is the term for helical grooves machined into the internal surface of a firearms's barrel for imparting a spin to a projectile to improve its aerodynamic stability and accuracy. It is also the term (as a verb) for creating such groov ...

gun barrel A gun barrel is a crucial part of gun-type weapons such as small arms, small firearms, artillery pieces, and air guns. It is the straight shooting tube, usually made of rigid high-strength metal, through which a contained rapid expansion of high ...

s. Decoppering agents are frequently added to

smokeless powder Finnish smokeless powder Smokeless powder is a type of propellant used in firearms and artillery that produces less smoke and less fouling when fired compared to black powder. Because of their similar use, both the original black powder formula ...

propellant A propellant (or propellent) is a mass that is expelled or expanded in such a way as to create a thrust or another motive force in accordance with Newton's third law of motion, and "propel" a vehicle, projectile, or fluid payload. In vehicle ...

s. Decoppering is most important for large guns (especially

naval gun Naval artillery is artillery mounted on a warship, originally used only for naval warfare and then subsequently used for more specialized roles in surface warfare such as naval gunfire support (NGFS) and anti-aircraft warfare (AAW) engagements. T ...

s), but the additives are used even in medium and small caliber guns. The most common decoppering additives are: *

Tin Tin is a chemical element; it has symbol Sn () and atomic number 50. A silvery-colored metal, tin is soft enough to be cut with little force, and a bar of tin can be bent by hand with little effort. When bent, a bar of tin makes a sound, the ...

metal and compounds, e.g.

tin dioxide Tin(IV) oxide, also known as stannic oxide, is the inorganic compound with the formula SnO2. The mineral form of SnO2 is called cassiterite, and this is the main ore of tin. With many other names, this oxide of tin is an important material in ti ...

Bismuth Bismuth is a chemical element; it has symbol Bi and atomic number 83. It is a post-transition metal and one of the pnictogens, with chemical properties resembling its lighter group 15 siblings arsenic and antimony. Elemental bismuth occurs nat ...

metal and compounds, e.g.

bismuth trioxide Bismuth(III) oxide is a compound of bismuth, and a common starting point for bismuth chemistry. It is found naturally as the mineral bismite (monoclinic) and sphaerobismoite (tetragonal, much more rare), but it is usually obtained as a by-product ...

, bismuth subcarbonate, bismuth nitrate, bismuth antimonide; the bismuth compounds are favored as copper dissolves in molten bismuth, forming

brittle A material is brittle if, when subjected to stress, it fractures with little elastic deformation and without significant plastic deformation. Brittle materials absorb relatively little energy prior to fracture, even those of high strength. ...

and easily removable

alloy An alloy is a mixture of chemical elements of which in most cases at least one is a metal, metallic element, although it is also sometimes used for mixtures of elements; herein only metallic alloys are described. Metallic alloys often have prop ...

Lead Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...

foil and lead compounds, although concerns have been raised about lead toxicity

References

{{reflist Ammunition