Saturday night special
A term popularised by the Detroit Police for an easily purchased and concealed, cheaply made 38-calibre/9-mm handgun often used for crimes of passions, many of which occur on Saturday nights.
The original Saturday night specials were revolvers, but the term has been genericised to include any cheaply made and readily acquired handgun. Detroit has a high rate of homicides, such that it was waggishly observed that Detroit has 2 types of death: “regular” and “unleaded”.
personal communication, former trainee in Detroit medical examiner’s office