Editing Slug barrel (section)

==Origins==
When slugs are fired in a standard, [[Shotgun#Pattern and choke|choke]]d barrel, the slug is deformed by the choke as it exits.  The degree of deformation is most acute with fuller chokes, which were among the most widely used in stock shotguns up until the 1980s and 1990s.  Early shotgun slugs were "rifled" with deformable fins cast into the outside of the soft [[lead]] slug, which allowed the slug to [[swage]] down to fit the choke.  With an open choke, the reduction in diameter is minimal, so accuracy does not suffer much; tighter chokes, however, deform the slug enough to impact accuracy significantly, and the impact of the slug on the choke (at velocities around 450 meters per second (1500 feet per second)) could also stretch the barrel with repeated firings.