You've obviously been re-reading my favorite novel- "The Godfather"--Michael's two Sicilian bodyguards carried short barreled shotguns with slings in the scenes staged in Sicily near Corleone (Heart of the Lion)--Also the name may come from their usage by Sicilian shepards against wolves- Lupo- is wolf in both Italian and the Sicilian dialect-- Che ti dice la Patria--


"The field is the touchstone of the man"..