Editing Cartridge (firearms) (section)

==Design==
===Purpose===
The cartridge was invented specifically for [[breechloading]] firearms. Prior to its invention, the projectiles and propellant were carried separately and had to be individually loaded [[muzzleloading|via the muzzle]] into the [[gun barrel]] before firing, then have a separate [[fire making|ignitor]] compound (from a burning [[slow match]], to a small charge of [[gunpowder]] in a [[flash pan]], to a metallic [[percussion cap]] mounted on top of a "nipple" or cone), to serve as a source of [[activation energy]] to set off the shot. Such loading procedures often require adding paper/cloth [[wadding]] and [[ramrod|ramming down repeatedly with a rod]] to optimize the [[seal (mechanical)|gas seal]], and are thus clumsy and inconvenient, severely restricting the practical [[rate of fire]] of the weapon, leaving the shooter vulnerable to the threat of [[close combat]] (particularly [[cavalry]] [[charge (warfare)|charge]]s) as well as complicating the logistics of ammunition.

The primary purpose of using a cartridge is to offer a handy pre-assembled "all-in-one" package that is convenient to handle and transport, easily loaded into the breech (rear end) of the barrel, as well as preventing potential propellant loss, contamination or degradation from [[moisture]] and the elements. In modern [[repeating firearm#Autoloading|self-loading firearm]]s, the cartridge case also enables the [[action (firearms)|action]] mechanism to use part of the [[propellant]]'s energy (carried inside the cartridge itself) and cyclically load new rounds of ammunition to allow quick repeated firing.

To perform a firing, the round is first inserted into a "ready" position within the [[chamber (firearms)|chamber]] aligned with the [[bore axis]] (i.e. "in ''battery''"). While in the chamber, the cartridge case [[obturation|obturate]]s all other directions except the [[gun barrel#Bore|bore]] to the front, reinforced by a [[breechblock]] or a locked [[bolt (firearms)|bolt]] from behind, designating the forward direction as the [[path of least resistance]]. When the [[trigger (firearms)|trigger]] is pulled, the [[sear (firearm)|sear]] disengages and releases the [[hammer (firearms)|hammer]]/[[firing pin|striker]], causing the [[firing pin]] to impact the [[primer (firearms)|primer]] embedded in the base of the cartridge. The [[shock sensitivity|shock-sensitive]] chemical in the primer then creates a [[jet (fluid)|jet]] of [[spark (fire)|spark]]s that travels into the case and ignites the main propellant charge within, causing the powders to ''[[deflagration|deflagrate]]'' (but not ''[[detonation|detonate]]''). This rapid [[exothermic]] [[combustion]] [[yield (chemistry)|yield]]s a mixture of highly energetic gases and generates a very high [[pressure]] inside the case, often [[fire forming|fire-forming]] it against the chamber wall. When the pressure builds up sufficiently to overcome the fastening [[friction]] between the projectile (e.g. bullet) and the case neck, the projectile will detach from the case and, pushed by the expanding high-pressure gases behind it, [[internal ballistics|move down the bore]] and out the [[muzzle (firearms)|muzzle]] at [[muzzle velocity|extremely high speed]]. After the bullet exits the barrel, the gases are released to the surroundings as [[ejecta]]e in a [[muzzle blast|loud blast]], and the chamber pressure drops back down to [[ambient pressure|ambient level]]. The case, which had been elastically expanded by high pressure, contracts slightly, which eases its removal from the chamber when pulled by the [[extractor (firearms)|extractor]]. The spent cartridge, with its projectile and propellant gone but the case still containing a used-up primer, then gets ejected from the gun to clear room for a subsequent new round.

=== Components ===
A modern cartridge consists of four main components: the ''case'', the ''projectile'', the ''propellant'', and the ''primer''.

==== Case ====
[[Image:Many bullets.jpg|thumb|Three non-bottlenecked cartridges ([[9×19mm Parabellum]], [[.40 S&W]] and [[.45 ACP]]) on the left, three bottlenecked cartridges ([[FN 5.7×28mm]], [[5.56×45mm NATO]] and [[.300 Winchester Magnum]]) in the center, and two [[polymer-cased ammunition|polymer-cased]] [[12-gauge]] [[shotshell]]s on the right]]
The main defining component of the cartridge is the case, which gives the cartridge its shape and serves as the integrating [[housing (engineering)|housing]] for other functional components, it acts as a container for the propellant powders and also serves as a protective [[shell (structure)|shell]] against the elements; it attaches the projectile either at the front end of the cartridge ([[bullet]]s for [[pistol]]s, [[submachine gun]]s, [[rifle]]s, and [[machine gun]]s) or inside of the cartridge ([[wadding]]/[[sabot (firearms)|sabot]] containing either a quantity of [[shot (pellet)|shot (pellets)]] or an individual [[shotgun slug|slug]] for [[shotgun]]s), and align it with the [[gun barrel#Bore|barrel bore]] to the front; it holds the [[primer (firearms)|primer]] at the back end, which receives an impact from a [[firing pin]] and is responsible for igniting the main propellant charge inside the case.

While historically [[cartridge paper|paper]] had been used in the [[paper cartridge|earliest cartridges]], almost all modern cartridges use [[metallic cartridge|metallic casing]]. The modern metallic case can either be a "bottleneck" one, whose frontal portion near the end opening (known as the "case ''neck''") has a noticeably smaller [[diameter]] than the main part of the case ("case ''body''"), with a noticeably angled slope ("case ''shoulder''") in between; or a "straight-walled" one, where there is no narrowed neck and the whole case looks [[cylindrical]]. The case shape is meant to match exactly to the [[chamber (firearms)|chamber]] of the gun that fires it, and the "neck", "shoulder", and "body" of a bottleneck cartridge have corresponding counterparts in the chamber known as the "chamber neck", "chamber shoulder", and "chamber body". 

Some cartridges, like the [[.470 Capstick]], have what is known as a "ghost shoulder" which has a very slightly protruding shoulder, and can be viewed as a something between a bottleneck and straight-walled case. A ghost shoulder, rather than a continuous taper on the case wall, helps the cartridge to line up concentrically with the bore axis, contributing to accuracy. The front opening of the case neck, which receives and fastens the bullet via [[crimp (joining)|crimping]], is known as the ''{{vanchor|case mouth}}''. The closed-off rear end of the case body, which holds the [[primer (firearms)|primer]] and technically is the case ''base'', is called the ''case head'' as it is the most prominent and frequently the widest part of the case. There is a circumferential [[flange]] at the case head called a ''[[rim (firearms)|rim]]'', which provides a lip for the [[extractor (firearms)|extractor]] to engage. Depending on whether and how the rim protrudes beyond the maximum case body diameter, the case can be classified as either "rimmed", "semi-rimmed", "rimless", "rebated", or "belted".

The shape of a bottleneck cartridge case (e.g. body diameter, shoulder slant angle and position, and neck length) also affects the amount of attainable pressure inside the case, which in turn influences the [[accelerative]] capacity of the projectile. [[Wildcat cartridge]]s are often made by reshaping the case of an existing cartridge. Straight-sided cartridges are less prone to rupturing than [[Tapering (firearms)|tapered cartridges]], in particular with higher pressure propellant when used in blowback-operated firearms.

In addition to case shape, [[rifle cartridge]]s can also be grouped according to the case dimensions of a cartridge, this is usually referring to the cartridge's overall length (COL), which in turn dictates the minimal [[receiver (firearms)|receiver]] size and operating space ([[bolt (firearms)|bolt]] travel) needed by the [[action (firearms)|action]], into either "mini-action", "short-action", "long-action" ("standard-action"), or "[[magnum cartridge|magnum]]-action" categories.
* ''Mini-action'' cartridges are usually [[intermediate cartridge|intermediate rifle cartridges]] with a COL of {{cvt|2.25|in|lk=on|order=flip}} or shorter in length, which is most commonly exemplified by the [[.223 Remington]];
* ''Short-action'' cartridges are usually [[fully powered cartridge|full-powered rifle cartridge]]s with a COL between {{cvt|2.25|and|2.8|in|order=flip}}, which is most commonly exemplified by the [[.308 Winchester]];
* ''Long-action'' ("standard-action") cartridges are usually traditional full-powered rifle cartridges with a COL between {{cvt|2.8|and|3.34|in|order=flip}}, which is most commonly exemplified by the [[.30-06 Springfield]];
* ''Magnum-action'' cartridges are rifle cartridges that are both longer, wider and more powerful than traditional long-action rifle cartridges, with a COL between {{cvt|3.34|and|3.6|in|order=flip}}, including some of the long-action cartridges with a case head larger than {{cvt|.50|in|order=flip}} diameter, which is most commonly exemplified by the [[.375 Holland & Holland Magnum]].<ref>{{cite web|url=https://blog.gunassociation.org/short-action-vs-long-action-rifles/|title=Short Action vs Long Action Rifles Explained|last=|first=|date=3 August 2020|publisher=American Gun Association|access-date=1 February 2021|archive-date=18 January 2021|archive-url=https://web.archive.org/web/20210118134927/https://blog.gunassociation.org/short-action-vs-long-action-rifles/|url-status=live}}</ref>

The most popular material used to make cartridge cases is [[brass]] due to its good [[corrosion resistance]]. The head of a brass case can be work-hardened to withstand the high pressures, and allow for manipulation via extraction and ejection without rupturing. The neck and body portion of a brass case is easily annealed to make the case [[ductile]] enough to allow reshaping so that it can be [[handloading|handloaded]] many times, and [[fire forming]] can help [[accurize]] the shooting.

Steel casing is used in some [[plinking]] ammunition, as well as in some military training ammunition (mostly from the [[former Soviet republics]] of Armenia, Azerbaijan, Belarus, Estonia, Georgia, Kazakhstan, Kyrgyzstan, Latvia, Lithuania, Moldova, Russia, Tajikistan, Turkmenistan, Ukraine, and Uzbekistan), along with Russia and China.{{Citation needed|date=September 2018}} Steel is less expensive to make than brass, but it is far less corrosion-resistant and not feasible to reuse and reload.  Military forces typically consider [[Service rifle|service]] [[small arms]] cartridge cases to be disposable, single-use devices. However, the mass of the cartridges can affect how much ammunition a soldier can carry, so the lighter steel cases do have a [[Military logistics|logistic]] advantage.<ref>{{Cite web |title=Mass, Weight, Density or Specific Gravity of Different Metals |url=https://www.simetric.co.uk/si_metals.htm |access-date=2022-11-07 |website=www.simetric.co.uk |archive-date=31 December 2018 |archive-url=https://web.archive.org/web/20181231175853/https://www.simetric.co.uk/si_metals.htm |url-status=live }}</ref> Conversely, steel is more susceptible to contamination and damage so all such cases are varnished or otherwise sealed against the elements.  One downside caused by the increased strength of steel in the neck of these cases (compared to the annealed neck of a brass case) is that [[propellant]] gas can blow back past the neck and leak into the chamber. Constituents of these gases condense on the (relatively cold) chamber wall, and this solid propellant residue can make extraction of fired cases difficult.  This is less of a problem for small arms of the former [[Warsaw Pact]] nations, which were designed with much looser chamber [[engineering tolerance|tolerance]]s than [[NATO]] weapons.{{Citation needed|date=September 2018}}

Aluminum-cased cartridges are available commercially. These are generally not reloaded, as aluminum [[fatigue (material)|fatigue]]s easily during firing and resizing.  Some calibers also have non-standard primer sizes to discourage reloaders from attempting to reuse these cases.

{{missing information|semi-combustible cases in [[120×570mm NATO]] tank shells: the body is polymer, but the base stays|date=March 2023}}
[[Polymer-cased ammunition|Plastic cases]] are commonly used in [[shotgun shell]]s, and some manufacturers offer [[polymer]]-cased [[centerfire]] pistol and rifle cartridges.<ref>Johnson, S. (2013, January 10). Extreme polymer research’s polymer handgun cartridge cases -. The Firearm Blog. https://www.thefirearmblog.com/blog/2011/09/23/extreme-polymer-researchs-polymer-handgun-cartridge-cases/ {{Webarchive|url=https://web.archive.org/web/20240204035450/https://www.thefirearmblog.com/blog/2011/09/23/extreme-polymer-researchs-polymer-handgun-cartridge-cases/ |date=4 February 2024 }}</ref><ref>Beckstrand, T. (2018, October 16). True velocity’s new polymer-cased ammunition. Guns and Ammo. https://www.gunsandammo.com/editorial/true-velocitys-new-polymer-cased-ammunition/247607 {{Webarchive|url=https://web.archive.org/web/20240204035450/https://www.gunsandammo.com/editorial/true-velocitys-new-polymer-cased-ammunition/247607 |date=4 February 2024 }}</ref>

==== 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.

==== 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]].

==== Primer ====
[[File:Percussion caps.jpg|thumb|right|Percussion caps, the precursor of modern primers]]
[[File:Centerfire & rimfire ignition.gif|thumb|Comparison of primer ignition between centerfire (left two) and rimfire (right) ammunitions]]
[[File:Berdan vs boxer2.jpg|thumb|Flash hole profiles on Berdan (left) and Boxer (right) primers.]]
{{main|Primer (firearm)}}{{see also|Percussion cap}}
Because the main propellant charge is located deep inside the [[gun barrel]] and thus impractical to be directly lighted from the outside, an intermediate is needed to relay the [[fire making|ignition]]. In the earliest [[black powder]] [[muzzleloader]]s, a [[fuse (explosives)|fuse]] was used to direct a small flame through a [[touch hole]] into the barrel, which was slow and subjected to disturbance from environmental conditions. The next evolution was to have a small separate charge of finer gunpowder poured into a [[flash pan]], where it could start a "priming" ignition by an external source, when ignited the flame passed through a small hole in the side of the barrel to ignite the main gunpowder charge. 

The last evolution was to use a small [[percussion cap|metallic cap]] filled with a shock sensitive explosive compound that would ignite with a [[Hammer (firearms)|hammer]] strike. The source of ignition could be a burning [[slow match]] ([[matchlock]]) placed onto a [[touch hole]], a piece of [[pyrite]] ([[wheellock]])/[[flint]] ([[flintlock]]) striking a steel [[frizzen]], or a [[shock sensitivity|shock-sensitive]] brass or copper percussion cap ([[caplock]]) placed over a conical-shaped cone piece with a hollow pipe to create [[spark (fire)|spark]]s. When the primer powder starts combusting, the flame is transferred through an internal touch hole called a ''flash hole'' to provide [[activation energy]] for the main powder charge in the barrel. The disadvantage Is that the flash pan cAN still be exposed to the outside, making it difficult (or even impossible) to fire the gun in rainy or humid conditions as wet gunpowder burns poorly.

After [[Edward Charles Howard]] discovered [[fulminate]]s in 1800<ref>Howard, Edward (1800) [https://archive.org/details/bub_gb_dlFFAAAAcAAJ/page/n220 <!-- pg=204 --> "On a New Fulminating Mercury"], ''Philosophical Transactions of the Royal Society of London'' '''90''' (1): 204–238.</ref><ref>[https://www.npg.org.uk/collections/search/person/mp02292/edward-charles-howard Edward Charles Howard] {{Webarchive|url=https://web.archive.org/web/20210514052233/https://www.npg.org.uk/collections/search/person/mp02292/edward-charles-howard |date=14 May 2021 }} at National Portrait Gallery</ref> and the patent by [[Reverend]] [[Alexander John Forsyth]] expired in 1807,<ref name="Fadala2006">{{cite book|last=Fadala|first=Sam|title=The Complete Blackpowder Handbook|url=https://books.google.com/books?id=Dzxyneq43AEC&pg=PA160|date=17 November 2006|publisher=Gun Digest Books|location=Iola, Wisconsin|isbn=0-89689-390-1|pages=159–161}}{{Dead link|date=November 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> [[Joseph Manton]] invented the precursor [[percussion cap]] in 1814,<ref>{{cite book|author=Sam Fadala|title=The Complete Blackpowder Handbook|url=https://books.google.com/books?id=Dzxyneq43AEC&pg=PA158|year=2006|publisher=Krause Publications|isbn=978-0-89689-390-0|page=158}}{{Dead link|date=November 2023 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> which was further developed in 1822 by the English-born American artist [[Joshua Shaw]],<ref>{{cite web|url=http://www.researchpress.co.uk/firearms/ignition/shaw02.htm |archive-url=https://web.archive.org/web/20120218221926/http://www.researchpress.co.uk/firearms/ignition/shaw02.htm |url-status=dead |archive-date=18 February 2012 |title=Joshua Shaw |access-date=5 November 2018}}</ref> and [[caplock]] [[fowling piece]]s appeared in [[Regency era]] England. These guns used a [[spring (device)|spring]]-loaded [[hammer (firearms)|hammer]] to strike a percussion cap placed over a [[conical]] "nipple", which served as both an "[[anvil]]" against the hammer strike and a transfer port for the sparks created by crushing the cap, and was easier and quicker to load, more resilient to weather conditions, and more reliable than the preceding flintlocks.<ref name="Fadala2006"/>

Modern primers are basically improved percussion caps with [[shock sensitivity|shock-sensitive]] chemicals (e.g. [[lead styphnate]]) enclosed in a small button-shaped capsule. In the early [[paper cartridge]]s, invented not long after the percussion cap, the primer was located deep inside the cartridge just behind the bullet, requiring a very thin and elongated [[firing pin]] to pierce the paper casing. Such guns were known as [[needle gun]]s, [[Dreyse needle gun|the most famous of which]] was decisive in the [[Kingdom of Prussia|Prussia]]n victory over the [[Austrian Empire|Austria]]ns at [[Battle of Königgrätz|Königgrätz]] in 1866. After the metallic cartridge was invented, the primer was relocated backward to the base of the case, either at the center of the case head ([[centerfire]]), inside the rim ([[rimfire ammunition|rimfire]]), inside a cup-like concavity of the case base (cupfire), in a pin-shaped sideways projection ([[pinfire]]), in a lip-like [[flange]] ([[Ethan Allen (armsmaker)#Cartridge pistols|lipfire]]), or in a small nipple-like bulge at the case base ([[teat-fire]]). Today, only the centerfire and rimfire have survived as the mainstream primer designs, while the pinfire also still exists but only in rare novelty miniature guns and a few very small [[blank cartridge]]s designed as noisemakers.

In rimfire ammunitions, the primer compound is [[injection moulding|moulded]] integrally into the interior of the protruding [[rim (firearms)|case rim]], which is crushed between the firing pin and the edge of the barrel breech (serving as the "anvil"). These ammunitions are thus not [[handloading|reload]]able, and are usually on the lower end of the [[muzzle energy|power]] spectrum, although due to the low [[manufacturing cost]] some of them (e.g. [[.22 Long Rifle]]) are among the most popular and prolific ammunitions currently being used.

Centerfire primers are a separately manufactured component, seated into a central recess at the case base known as the ''primer pocket'', and have two types: Berdan and Boxer. Berdan primers, patent by American inventor [[Hiram Berdan]] in 1866, are a simple capsule, and the corresponding case has two small flash holes with a bulged bar in between, which serves as the "anvil" for the primer. Boxer primers, patented by [[Royal Artillery]] colonel [[Edward Mounier Boxer]] also in 1866, are more complex and have an internal tripedal "anvil" built into the primer itself, and the corresponding case has only a single large central flash hole. Commercially, Boxer primers dominate the [[handloading|handloader]] market due to the ease of depriming and the ability to transfer sparks more efficiently.

Due to their small size and charge load, primers lack the power to shoot out the projectile by themselves, but can still put out enough energy to separate the bullet from the casing and push it partway into the barrel – a dangerous condition called a [[squib load]]. Firing a fresh cartridge behind a squib load obstructing the barrel will generate dangerously high pressure, leading to a [[catastrophic failure]] and potentially causing severe injuries when the gun blows apart in the shooter's hands. Actor [[Brandon Lee]]'s [[The Crow (1994 film)#Brandon Lee's death|infamous accidental death in 1993]] was believed to be caused by an undetected squib that was dislodged and shot out by a [[blank (cartridge)|blank]].

===Manufacturing===
[[File:0.30-30 Winchester case, stages in the drawing process, book; Cartridge Manufacture (1916), author; Douglas T. Hamilton.png|thumb|upright=1.6|.30–30 Winchester case, stages in the drawing process, book; from Hamilton<ref name=":0">{{Cite book |url=http://archive.org/details/cartridgemanufac00hamirich |title=Cartridge manufacture; a treatise covering the manufacture of rifle cartridge cases, bullets, powders, primers and cartridge clips, and the designing and making of the tools used in connection with the production of cartridge cases and bullets |last=Hamilton |first=Douglas Thomas |date=1916 |location=New York |publisher=The Industrial Press |access-date=8 April 2019 |archive-url=https://web.archive.org/web/20170606192744/https://archive.org/details/cartridgemanufac00hamirich |archive-date=6 June 2017 |url-status=live }}</ref>]]
Beginning in the 1860s, early metallic cartridges (e. g. for the [[Montigny mitrailleuse]]<ref>{{cite web | url=https://www.victorianshipmodels.com/antitorpedoboatguns/Mitrailleuse/mitrailleuseammu.html | title=Mitrailleuse Ammunition | access-date=10 August 2022 | archive-date=18 October 2021 | archive-url=https://web.archive.org/web/20211018081700/http://www.victorianshipmodels.com/antitorpedoboatguns/Mitrailleuse/mitrailleuseammu.html | url-status=live }}</ref> or the [[Snider–Enfield]] rifle<ref>{{cite web | url=https://sites.google.com/site/britmilammo/-577-inch-snider/-577-inch-ball-pattern-i-to-v | title=British Military Small Arms Ammo - .577 inch Ball Pattern I to V | access-date=10 August 2022 | archive-date=10 August 2022 | archive-url=https://web.archive.org/web/20220810113235/https://sites.google.com/site/britmilammo/-577-inch-snider/-577-inch-ball-pattern-i-to-v | url-status=live }}</ref>) were produced similarly to the paper cartridges, with sides made from thick paper, but with copper (later brass) foil supporting the base of the cartridge and some more details in it holding the primer. In the 1870s, brass foil covered all of the cartridge, and the technology to make solid cases, in which the metallic cartridges described below were developed, but before the 1880s, it was far too expensive and time-consuming for mass production<ref>{{cite web | url=https://sites.google.com/site/britmilammo/-450-inch-martini-henry/-45-martini-henry-drawn-case | title=British Military Small Arms Ammo - .45 Martini-Henry Solid Case Rifle | access-date=10 August 2022 | archive-date=10 August 2022 | archive-url=https://web.archive.org/web/20220810113236/https://sites.google.com/site/britmilammo/-450-inch-martini-henry/-45-martini-henry-drawn-case | url-status=live }}</ref> and the metallurgy was not yet perfected.<ref>{{cite web | url=http://www.victorianshipmodels.com/antitorpedoboatguns/Hotchkiss/hotchkissammunit.html | title=Hotchkiss Ammunition | access-date=10 August 2022 | archive-date=5 May 2022 | archive-url=https://web.archive.org/web/20220505235020/http://www.victorianshipmodels.com/antitorpedoboatguns/Hotchkiss/hotchkissammunit.html | url-status=live }}</ref>

To manufacture cases for cartridges, a sheet of brass is punched into disks. These disks go through a series of [[deep drawing|drawing dies]]. The disks are [[annealing (metallurgy)|annealed]] and washed before moving to the next series of dies. The brass needs to be annealed to remove the work-hardening in the material and make the brass malleable again ready for the next series of dies.<ref name=":0"/>

Manufacturing bullet jackets is similar to making brass cases: there is a series of drawing steps with annealing and washing.<ref name=":0" />

===Specifications===
Critical cartridge specifications include neck size, bullet weight and [[caliber]], maximum pressure, [[headspace (firearms)|headspace]], overall length, case body diameter and taper, shoulder design, [[Rim (firearms)|rim type]], etc. Generally, every characteristic of a specific cartridge type is tightly controlled and few types are interchangeable in any way. Exceptions do exist but generally, these are only where a shorter cylindrical rimmed cartridge can be used in a longer chamber, (e.g., .22 Short in .22 Long Rifle chamber, .32 H&R Magnum in .327 Federal Magnum chamber, and .38 Special in a .357 Magnum chamber). [[Centerfire ammunition|Centerfire]] primer type (Boxer or Berdan, see below) is interchangeable, although not in the same case. Deviation in any of these specifications can result in firearm damage and, in some instances, injury or death. Similarly, the use of the wrong type of cartridge in any given gun can damage the gun, or cause bodily injury.

Cartridge specifications are determined by several standards organizations, including [[SAAMI]] in the United States, and [[C.I.P.]] in many European states. NATO also performs [[NATO EPVAT testing|its own tests]] for military cartridges for its member nations; due to differences in testing methods, NATO cartridges ([[headstamp]]ed with the NATO cross) may present an unsafe combination when loaded into a weapon chambered for a cartridge certified by one of the other testing bodies.<ref>{{cite web|url=http://www.saami.org/specifications_and_information/publications/download/SAAMI_ITEM_211-Unsafe_Arms_and_Ammunition_Combinations.pdf |title=Unsafe Firearm-Ammunition Combinations |publisher=SAAMI |date=6 March 2012 |access-date=4 November 2013 |url-status=dead |archive-url=https://web.archive.org/web/20131116092917/http://saami.org/specifications_and_information/publications/download/SAAMI_ITEM_211-Unsafe_Arms_and_Ammunition_Combinations.pdf |archive-date=16 November 2013}}</ref>

Bullet diameter is measured either as a fraction of an inch (usually in 1/100 or in 1/1000) or in millimeters. Cartridge case length can also be designated in inches or millimeters.