One Hell of a Shotgun

Every so often, in various stories, I see references to a ".12 gauge" shotgun. I've always assumed that was sloppy editing or typesetting, if not writing.

But then I became curious: What would the bore diameter of a .12 gauge shotgun be?

Shotgun gauges (other than .410) are a function of the weight of a lead round ball of the diameter of the shotgun's bore. Simply put, it is how many such round balls it would take to equal a pound. A 12 gauge means that it would take twelve such balls. So 1 pound of pure lead = 1/x, where "x" ix the gauge number.

First off, a ".12 gauge" shotgun would throw a 8.3 lb ball of lead.

There is, of course, an equation for the bore diameter. It is the inverse of the cube root of the gauge number, times 1.66992. Running that on a .12 gauge gives a bore diameter of 3.38".

Which would be one hell of a gun to shoot from the shoulder.

A different formula from Wikipedia yields the same result, with "n" as the bore number.