In reviewing old Union Metallic Cartridge Co. catalogues and price lists, the first time I see mention of extra length paper shot shell cases is in the 1880 catalogue, before they were even offering loaded shot shells. Smokeless powder loaded shot shells begin appearing in the 1891 catalogue. While the “standard” 12-gauge shells were in 2 5/8 or 2 3/4 inch lengths, the “standard” 16-gauge was 2 9/16 inch and the “standard” 20-gauge was 2 1/2 inch, paper 12-gauge shells were offered in 2 5/8, 2 3/4, 2 7/8, 3 and 3 1/4 inch lengths; 16-gauge shells in 2 9/16, 2 3/4, 2 7/8 and 3-inch lengths; and 20-gauge shells in 2 1/2, 2 3/4, 2 7/8 and 3-inch lengths.
From the 1890s into the early 1920s, these longer shot shells didn't carry a heavier payload than one could get in a 2 3/4 inch 12-gauge shell, just more/better wadding, which many serious Pigeon shooters believed to be an advantage.
