In Europe, a lot of the 28 gauge guns were chambered and proofed at 2 1/2".
The 2 1/2 inch 28-gauge shell with a load of 1 3/4 drams of bulk smokeless powder pushing 5/8 ounce of shot was the "standard" in the U.S. from the 28-gauges's introduction until 1932. Unlike the 12-, 16- and 20-gauge shells in the first thirty years of the 20th Century which came in a plethora of lengths, the only optional length our North American ammunition companies offered for the 28-gauge was 2 7/8 inch which could be had with a slightly hotter 2 dram load pushing the same 5/8 ounce load. With bulk smokeless powder --
With dense smokeless powder --
In late 1931, Western Cartridge Co. introduced their 3/4 ounce 28-gauge progressive burning powder, high velocity, Super-X load put up in their 2 7/8 inch FIELD shell.
Shortly before the U.S. got into WW-II our ammunition companies began offering 28-gauge skeet loads put up in a 2 3/4 inch shell and shortly after WW-II they did away with the 2 1/2 and 2 7/8 inch lengths and standardized the 28-gauge in a 2 3/4 inch hull.
