Editing Cartridge (firearms) (section)

==== Propellant ====
{{Main|Firearm propellant}}
[[Image:Powder Samples.jpg|thumb|Smokeless powders used for [[handloading]]]]

When a propellant is ignited and begins to [[combustion|combust]], the resulting [[chemical reaction]] releases the [[chemical energy]] stored within. At the same time, a significant amount of gaseous [[product (chemistry)|product]]s are released, which are highly energetic due to the [[exothermic]] nature of the reaction. These combustion gases become highly pressurized in a confined space—such as the cartridge casing (reinforced by the [[chamber (firearms)|chamber]] wall) occluded from the front by the projectile (bullet, or [[wadding]] containing [[shot (pellet)|shot]]s/[[shotgun slug|slug]]) and from behind by the [[Primer (firearms)|primer]] (supported by the [[bolt (firearms)|bolt]]/[[breechblock]]). When the pressure builds up high enough to overcome the [[crimp (joining)|crimp]] friction between the projectile and the case, the projectile separates from the case and gets ''propelled'' down the [[gun barrel]], imparting high [[kinetic energy]] from the propellant gases and accelerating the projectile to its [[muzzle velocity]]. The projectile motion driven by the propellant inside the gun is known as the [[internal ballistics]].