Convert from cana (canna, canne) to caliber

Unit Definition (cana (canna, canne))
The caña (canna, canne) are traditional units of distance in Spain, Italy, and southern France, respectively. The caña varied in size, but it was most often defined as 8 palmos, which makes it the Mediterranean version of the fathom, equal to roughly 2 meters or 6.5 feet. In Italy a measuring stick is still called a canna metrica. The unit is sometimes translated to "rod" in English, but "fathom" is the proper choice.

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."