We will know we have truly arrived when we are able to discuss the diameter of the muzzle end of the barrels with one guy using the term gauge and the other using the term bore and no one even notices. It is truly a non-issue except for some who are living in the past and have some residual resentment for colonial times and other perceived British misdeeds or who have some distorted notion of the romanticism of 19th and early 20th century aristocratic English driven shoots. Let it go guys. I don't care....I'm clear on the meaning of both terms in shotgun discussions........EXACTLY the same thing. I'm taking my 12 bore and my 20 gauge to my next shoot.