Editing Cartridge (firearms) (section)

==== Projectile ====
{{main|Bullet|Shot (pellet)|Shotgun slug}}
As firearms are projectile weapons, the projectile is the effector component of the cartridge, and is actually responsible for reaching, impacting, and exerting damage onto a target. The word "projectile" is an [[umbrella term]] that describes any type of [[projectile|kinetic object]] launched into [[projectile motion|ballistic flight]], but due to the ubiquity of [[rifled]] firearms shooting bullets, the term has become somewhat a technical [[synonym]] for bullets among [[handloading|handloaders]].  The projectile's motion in flight is known as its [[external ballistics]], and its behavior upon impacting an object is known as its [[terminal ballistics]].

A bullet can be made of virtually anything (see [[#Projectile design types|below]]), but [[lead]] is the traditional material of choice because of its high density, [[malleability]], [[ductility]], and low [[cost of production]]. However, at speeds greater than {{cvt|300|m/s}}, pure lead will melt more and deposit [[fouling]] in rifled bores at an ever-increasing rate. [[Alloying]] the lead with a small percentage of [[tin]] or [[antimony]] can reduce such fouling, but grows less effective as velocities are increased. A cup made of harder metal (e.g. copper), called a ''gas check'', is often placed at the base of a lead bullet to decrease lead deposits by protecting the rear of the bullet against melting when fired at higher pressures, but this too does not work at higher velocities. A modern solution is to cover the bare lead in a protective [[powder coat]], as seen in some rimfire ammunitions. Another solution is to encase a lead core within a thin exterior layer of harder metal (e.g. [[gilding metal]], [[cupronickel]], [[copper alloys]] or steel), known as a ''[[jacketing]]''. In modern days, steel, [[bismuth]], [[tungsten]], and other exotic alloys are sometimes used to replace lead and prevent [[lead poisoning|release of toxicity]] into the environment. In [[armor-piercing bullet]]s, very hard and high-density materials such as [[hardened steel]], [[tungsten]], [[tungsten carbide]], or [[depleted uranium]] are used for the penetrator core.

[[Non-lethal weapon|Non-lethal]] projectiles with very limited [[penetration (weaponry)|penetrative]] and [[stopping power]]s are sometimes used in [[riot control]] or training situations, where killing or even wounding a target at all would be undesirable. Such projectiles are usually made from softer and lower-density materials, such as [[plastic bullet|plastic]] or [[rubber bullet|rubber]]. [[Wax bullet]]s (such as those used in [[Simunition]] training) are occasionally used for force-on-force [[tactical engagement simulation|tactical training]]s, and [[pistol dueling]] with wax bullets used to be a [[shooting sport|competitive]] [[Olympic sport]] prior to [[World War I]].

For [[smoothbore]] weapons such as shotguns, small metallic balls known as [[shot (pellet)|shot]]s are typically used, which is usually contained inside a semi-flexible, cup-like [[sabot (firearms)|sabot]] called "[[wadding]]". When fired, the wadding is launched from the gun as a payload-carrying projectile, loosens and opens itself up after exiting the barrel, and then [[inertia]]lly releases the contained shots as a hail of sub-projectiles. Shotgun shots are usually made from bare lead, though copper/[[zinc]]–[[total metal jacket|coated]] steel balls (such as those used by [[BB gun]]s) can also be used. Lead pollution of wetlands has led to the [[British Association for Shooting and Conservation|BASC]] and other organizations campaigning for the phasing out of traditional lead shot.<ref>{{cite web|title= Lead|url= https://basc.org.uk/lead/|website= www.basc.org.uk|accessdate= 18 April 2021|archive-date= 18 April 2021|archive-url= https://web.archive.org/web/20210418204107/https://basc.org.uk/lead/|url-status= live}}</ref> There are also unconventional projectile fillings such as bundled [[flechette#Shotguns|flechette]]s, [[riot gun#Rubber buckshot|rubber balls]], [[rock salt]] and [[magnesium]] shards, as well as [[non-lethal weapon|non-lethal]] [[shotgun#Specialty ammunition|specialty projectiles]] such as [[baton round|rubber slug]]s and [[bean bag round]]s. Solid projectiles (e.g. [[shotgun slug|slug]]s, [[baton round]]s, etc.) are also shot while contained within a wadding, as the wadding [[obturate]]s the bore better and typically [[sliding (motion)|slide]]s less frictionally within the barrel.