The Meaning of Gauge and Caliber (Ed Zern)
Quite often, neophyte hunters are confused by the meanings of various gauge and caliber designations. Actually, these are extremely simple to understand, once you get the hang of it.
The gauge of a shotgun was originally designated by the number of lead balls, each fitting the bore of the gun, required to weigh one pound. The exception to this is the 12 gauge, in which the designation refers to the number of lead balls, each fitting the bore of the gun, required to make an even dozen.
In designations applied to rifles and ammunition, the figures may apply to diameter of the bore in inches, diameter of the bore in millimeters, the charge of the powder in grains, or anything else that happened to pop into the manufacturer's head.
For example, the 30-06 is derived from the fact that there are 30 days in April, and "06" is 60 (the number of characters in the Persian alphabet during the first part of the 13th century) backwards.
The 45/70/350 is so called because there are 45 congressional districts in New York State, 70 is the cube root of 343,000, and on January 10th there are only 350 shopping days until Christmas, if you include Sundays and holidays.
In short, the less said about this phase of hunting, the better for everybody concerned.
From "To Hell With Hunting" Copyright 1946, Pg. 29