Convert from arms-length to caliber

Unit Definition (arms-length)
An Arms length is standardized as a unit of distance equal to approximately 70 centimeters, or 28 inches. An arms length is the same as the modern Italian Braccio and very similar to the Turkish Pik.

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."