Editing Shotgun slug (section)

====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.