A wild guess. Shooting without being able to see is taking a long shot, at best. The term has been around since the late nineteenth century. It is the title of a hilarious 1964 film starring Peter Sellers as a bumbling detective, Inspector Clouseau, who is convinced that a beautiful woman (played by Elke Sommer) is innocent of murder despite all evidence to the contrary. Graham Greene used the expression in The Third Man (1950): “It was a shot in the dark, but already he had this firm instinctive sense that there was something wrong.”