History lesson --
From the late 1890s until after WW-I, the heaviest 16-gauge loads our North American ammunition companies offered were 2 3/4 drams of bulk smokeless powder or 22 grains of dense smokeless powder such as Infallible or Ballistite, pushing 1 ounce of shot. Those loads could be had in the "standard" 2 9/16 inch case or any of the longer 2 3/4, 2 7/8 or 3-inch cases. In late 1922 or early 1923, Western Cartridge Co. added the 16-gauge to their progressive burning powder loads called Super-X, but unlike the 1 1/4 ounce 12-gauge and 1 ounce 20-gauge Super-X loads which were put up in Western's 2 3/4 inch FIELD shells, the 1 1/8 ounce 16-gauge Super-X load was put up in their 2 9/16 inch FIELD shell. When the Lubaloy shot Super-X loads were introduced in July 1929, they were put up in Western's high brass RECORD shell, but the 16-gauge still in a 2 9/16 inch length case.
The 2 3/4 inch 16-gauge shell really began to get some traction when Remington Arms Co., Inc. introduced their Model 11 and "Sportsman" autoloaders in 16-gauge in 1931, chambered for 2 3/4 inch shells. While Remington's regular Nitro Express 16-gauge progressive burning powder load was put up in a 2 9/16 inch hull with a load of 3 drams equiv. pushing 1 1/8 ounce of shot, for their new 16-gauge autoloaders they introduced the slightly faster Auto-Express with a 3 1/4 drams equiv. charge pushing 1 1/8 ounce of shot --
I'm thin on Winchester ammo catalogues, but for sure by 1934, they were offering a similar 2 3/4 inch 16-gauge load.
The 2 3/4 inch Magnum shells with 1 1/2 ounce in 12-gauge, 1 1/4 ounce in 16-gauge and 1 1/8 ounce in 20-gauge first appear in the December 15, 1954, Western Cartridge Co. catalogues.
