Editing Shotgun slug (section)

==Types==
===Full-bore slugs===
Full-bore slugs such as the Brenneke and Foster designs use a [[Spin stabilization|spin-stabilization]] method of stabilization through the use of angled fins on the slug’s outer walls. The slight 750 [[Revolutions per minute|RPM]] spin is enough to stabilize the slug because the slug’s [[Center of pressure (fluid mechanics)|center of pressure]] is so much further back than its [[center of mass]].<ref>{{Citation |title=Yes, RIFLED Shotgun Slugs Spin - But how fast? |url=https://www.youtube.com/watch?v=EhpSQZ82i-s |language=en |access-date=2022-12-26}}</ref> [[Sabot (firearms)|Saboted]] slugs are similar in shape to handgun bullets and airguns pellets. Their center of pressure is in front of their center of mass, meaning a higher [[twist rate]] is required to achieve proper stabilization. Most saboted slugs are designed for [[Rifling|rifled]] shotgun barrels and are stabilized through gyroscopic forces from their spin.<ref name=":0">{{Cite web |last=Carter |first=Molly |date= |title=Sabot Slug Ammo: Sabot Slug Bullets Explained |url=https://ammo.com/bullet-type/sabot-slug |website=AMMO.COM}}</ref><ref>{{Citation |title=How Pellets and Slugs are Stabilized {{!}} AB101 Pt.9 |url=https://www.youtube.com/watch?v=Ur6iIcVhHmM |language=en |access-date=2022-12-26}}</ref>

====Brenneke slugs====
[[Image:Brenneke.jpg|thumb|right|250px|A 12 gauge Brenneke slug]]
The Brenneke slug was developed by the [[Germany|German]] gun and ammunition designer [[Wilhelm Brenneke]] (1865–1951) in 1898. The original Brenneke slug is a solid lead slug with ribs cast onto the outside, much like a rifled Foster slug.<ref>{{Cite web |title=History {{!}} Brenneke - Ammunition |url=https://www.brennekeusa.com/company/history/ |access-date=2022-12-26 |website=www.brennekeusa.com}}</ref> There is a plastic, felt or cellulose fiber wad attached to the base that remains attached after firing. This wad serves as a gas seal, preventing the gasses from going around the projectile. The lead "ribs" that are used for inducing spin also [[swage]] through any choked bore from improved cylinder to full. The soft metal, typically lead, fins squish or [[Swaging|swage]] down in size to fit through the choke to allow for an easy passage.<ref>{{Cite web |title=Orange Lightning {{!}} Brenneke - Ammunition |url=https://www.brennekeusa.com/hunting-ammunition/orange-lightningr/ |access-date=2022-12-26 |website=www.brennekeusa.com}}</ref>

====Foster slugs====
[[File:870bad.jpg|thumb|A Remington 870 12 gauge with sighted cylinder bore barrel suitable for Foster slugs and buckshot]]
The "Foster slug", invented by Karl M. Foster in 1931, and patented in 1947 ({{US Patent|2414863}}), is a type of shotgun slug designed to be fired through a smoothbore shotgun barrel, even though it commonly labeled as a "rifled" slug. A rifled slug is for smooth bores and a sabot slug is for rifled barrels.<ref name=":0" /> 

Most Foster slugs also have "[[rifling]]", which consists of ribs on the outside of the slug. Like the Brenneke, these ribs impart a rotation on the slug to correct for manufacturing irregularities, thus improving precision (i.e. group size).<ref name="NCJRS2">{{cite web|author=US DOJ, Federal Bureau of Investigation | title= Crime Laboratory Digest | date=April 1991 |volume=18 | number=2| page=37 |url= https://www.ncjrs.gov/pdffiles1/Digitization/132229NCJRS.pdf |access-date=24 February 2017| quote= The slight rotation imparted by the ribs reduces the effect of manufacturing irregularities. In tests performed by Winchester-Western, the slug rotation was confirmed, resulting in consistently smaller groups for rifled slugs than unrifled slugs... }}</ref> Similar to traditional rifling, the rotation of the slug imparts gyroscopic stabilization.

===Saboted slugs===
Saboted slugs are shotgun projectiles smaller than the bore of the shotgun and supported by a plastic sabot. The sabot is traditionally designed to engage the rifling in a rifled shotgun barrel and impart a ballistic spin onto the projectile. This differentiates them from traditional slugs, which are not designed to benefit from a rifled barrel (though neither does the other any damage). Due to the fact that they do not contact the bore, they can be made from a variety of materials including lead, copper, brass, or steel. Saboted slugs can vary in shape, but are typically bullet-shaped for increased [[ballistic coefficient]] and greater range. The sabot is generally plastic and serves to seal the bore and keep the slug centered in the barrel while it rotates with the rifling. The sabot separates from the slug after it departs the muzzle. Saboted slugs fired from rifled bores are superior in accuracy over any smooth-bored slug options with accuracy approaching that of low-velocity rifle calibers.<ref name=":0" />

===Wad slugs===
{{Unreferenced section|date=January 2021}}
[[Image:Plumbata shotgun slugs.JPG|thumb|right|250px|From the left, plumbata discarding sabot (No. 1); plumbata slugs (No. 2, No. 5); wad slug (No. 3), sabot slugs (No. 3, No. 4)]]
A modern variant between the Foster slug and the sabot slug is the wad slug. This is a type of shotgun slug designed to be fired through a smoothbore shotgun barrel. Like the traditional Foster slug, a deep hollow is located in the rear of this slug, which serves to retain the center of mass near the front tip of the slug much like the Foster slug. However, unlike the Foster slug, a wad slug additionally has a key or web wall molded across the deep hollow, spanning the hollow, which serves to increase the structural integrity of the slug while also reducing the amount of expansion of the slug when fired, reducing the stress on the shot wad in which it rides down a barrel. Also, unlike Foster slugs that have thin fins on the outside of the slug, much like those on the Brenneke, the wad slug is shaped with an [[ogive]] or bullet shape, with a smooth outer surface. The wad slug is loaded using a standard shotshell wad, which acts like a sabot. The diameter of the wad slug is slightly less than the nominal bore diameter, being around {{convert|0.690|in|mm|abbr=on}} for a 12-gauge wad slug, and a wad slug is generally cast solely from pure lead, necessary for increasing safety if the slug is ever fired through a choked shotgun. Common 12 gauge slug masses are {{frac|7|8}} oz (({{convert|383|gr|g|abbr=on}}), 1 oz (({{convert|437.5|gr|g|abbr=on}}), and {{frac|1|1|8}} oz (({{convert|492|gr|g|abbr=on}}), the same as common birdshot payloads. Depending on the specific stack-up, a card wad is also sometimes located between the slug and the shotshell wad, depending largely on which hull is specified, with the primary intended purpose of improving fold crimps on the loaded wad slug shell that serves to regulate fired shotshell pressures and improve accuracy.

It is also possible to fire a wad slug through rifled slug barrels, and, unlike with the Foster slug where lead fouling is often a problem, a wad slug typically causes no significant leading, being nested inside a traditional shotshell wad functioning as a sabot as it travels down the shotgun barrel.

Accuracy of wad slugs falls off quickly at ranges beyond {{convert|75|yd|m|abbr=on}}, thereby largely equaling the ranges possible with Foster slugs, while still not reaching the ranges possible with traditional sabot slugs using thicker-walled sabots.

Unlike the Foster slug which is traditionally roll-crimped, the wad slug is fold-crimped. Because of this important difference, and because it uses standard shotshell wads, a wad slug can easily be reloaded using any standard modern shotshell reloading press without requiring specialized roll-crimp tools.

===Plumbata slugs===
A [[plumbata]] slug has a plastic stabilizer attached to the projectile. The stabilizer may be fitted into a cavity in the bottom of the slug, or it may fit over the slug and into external notches on the slug. With the first method discarding sabots may be added. And with the second, the stabilizer may act as a sabot, but remains attached to the projectile and is commonly known as an "Impact Discarding Sabot" (IDS).<ref>{{Cite web |date=2018-09-27 |title=REFERENCE: Shotgun slugs and chokes |url=https://ozgunlobby.com/t/reference-shotgun-slugs-and-chokes/712 |access-date=2022-12-26 |website=Oz Gun Lobby |language=en}}</ref>

===Steel slugs===
There are some types of all-steel subcaliber slugs supported by a protective plastic sabot (the projectile would damage the barrel without a sabot). Examples include Russian "Tandem" wadcutter-type slug (the name is historical, as early versions consisted of two spherical steel balls) and ogive "UDAR" ("Strike") slug and French spool-like "Balle Blondeau" (Blondeau slug) and "Balle fleche Sauvestre" (Sauvestre flechette) with steel sabot inside expanding copper body and plastic rear empennage. Made of non-deforming steel, these slugs are well-suited to shooting in brush, but may produce [[Stopping Power#Overpenetration|overpenetration]]. They also may be used for disabling vehicles by firing in the engine compartment or for defeating hard body armor.{{Citation needed|date=January 2021}}

===Improvised slugs===
====Wax slugs====
Another variant of a Great Depression–era shotgun slug design is the wax slug. These were made by hand by cutting the end off a standard birdshot loaded shotshell, shortening the shell very slightly, pouring the lead shot out, and melting paraffin, candle wax, or crayons in a pan on a stovetop, mixing the lead birdshot in the melted wax, and then using a spoon to pour the liquified wax containing part of the birdshot back into the shotshell, all while not overfilling the shotgun shell. Once the shell cooled, the birdshot was now held in a mass by the cooled paraffin, and formed a slug. No roll or fold crimp was required to hold the wax slug in the hull. These were often used to hunt deer during the Depression.

====Cut shell slugs====
Yet another expedient shotgun slug design is the cut shell. These are made by hand from a standard birdshot shell by cutting a ring around and through the hull of the shell that nearly encircles the shell, with the cut traditionally located in the middle of the wad separating the powder and shot. A small amount of the shell wall is retained, amounting to roughly a quarter of the circumference of the shotshell hull. When fired, the end of the hull separates from the base and travels through the bore and down range. Cut shells have the advantage of expedience. They can be handmade on the spot as the need arises while on a hunt for small game if a larger game animal such as a deer or a bear appears. In terms of safety, part of the shell may remain behind in the barrel, causing potential problems if not noticed and cleared before another shot is fired.<ref name="fireenc">{{cite book|publisher=Harper & Row|isbn=978-0-06-013213-2|title=Firearms encyclopedia|author=George C. Nonte|year=1973|page=[https://archive.org/details/firearmsencyclop0000nont/page/76 76]|quote=A shotshell which has been cut partially through forward of the head in hope of reducing shot dispersion.|url=https://archive.org/details/firearmsencyclop0000nont/page/76}}</ref><ref>{{cite book|title=Textbook of firearms investigation, identification and evidence: together with the Textbook of pistols and revolvers, Volume 3|author=Julian Sommerville Hatcher|publisher=Small-arms technical publishing company|year=1935|page=61}}</ref>