I didn't forget it. 16 gauge was the standard that all others were judged by for about 75 years....12 gauge was 1 1/8 ounce & 20 gauge was 7/8. With the advent of smokeless powder and plastic hulls, 16 got squeezed into a nitch only for Edwardian Hunting enthusiasts. My best friend loves 16 SxS's, for their grace and balance with lighter weight and reasonable recoil. In the old days of Trap shooting 12 & 16 gauge were considered equal, but somewhere around the early 70's, Winchester quit making THE AA trap loads in 16 gauge. You can't shoot registered birds with reloads, so within 5 years the 16 gauge trap gun went the way of the Dodo bird! At Vintage shoots you see some real beauties, some with the most precise and pleasing Damascus barrels, but that right there tells you something about 16 gauge's demise!
16 gauge's popularity for hunting seemed to last 15 or 20 years longer in Europe, but the catalogs only list 16 gauge guns as a footnote. Nobody seems to be ordering Best Quality guns in 16 either.
I came to shotgunning for sport later in life, and by that time the American 16 gauge SxS was built only on 12 gauge actions, they were heavy and ammo availability was limited....Skeet and Sporting Clays are the only thing that saved 28 and 410 from the same fate!
Ivan