Convert from caliber to league [UK]

Unit Definition (caliber)
The caliber is a unit used to express the bore diameter of a gun. Traditionally, the diameter is stated in inches, so that ".22 caliber" refers to a pistol having a bore of 0.22 inches (5.588 mm). So the caliber is actually equivalent to the inch. The usage of the term "caliber" is actually now in decline, because bore diameters of many guns are now stated in millimeters. "Caliber" is the American spelling; elsewhere the unit is often spelled "calibre."

Unit Definition (league [UK])
The league became a common unit of measurement throughout western Europe, although its length varied greatly from region to region. It was originally intended to represent the distance a person could walk in an hour. In many cases it was equal to 3 miles, (note that the definition of a mile also varied from region to region). At sea, the league was often equal to 3 nautical miles, which is 1/20 degree or 5556 meters (metres). In the USA and Great Britain, the league is defined to be 3 statute miles on land, or 3 nautical miles at sea.