Just to confuse things, while most of our ammunition companies put up their progressive burning powder, high velocity, 1-ounce, 20-gauge loads in a 2 3/4-inch case, Winchester offered the load in both 2 3/4- and 2 1/2-inch shells.
Super-Speed 20-gauge, 2 1-2-inch, #7 1-2 Ch. Shot.jpg
Super-Speed 20-gauge, 2 3-4-inch, #6 Shot.jpg
Generally speaking, the 20-gauge 2 1/2-inch shells being offered in 1929 carried a load of 2 1/4 drams of bulk smokeless powder or 18-grains of dense smokeless powder such as Infallible of Ballistite with 3/4 or 7/8 ounce of shot.
NITRO CLUB 20-gauge, Load No. X23D.jpg
HIGH GUN 20-gauge, 2 1-2 inch, #7 1-2Ch, Ballistite.jpg