In the U.S. the standard 28-gauge shell from its introduction in the late 1890s to WW-II was a 2 1/2 inch shell with a 1 3/4 drams equiv. load and 5/8 ounces of shot. The manufacturers did offer 28-gauge 2 7/8 inch NPEs. Chas. Askins writes in his 1910 book
The American Shotgun about handloading 2 1/8 drams of bulk smokeless powder and 3/4 ounce of shot in 2 7/8 inch 28-gauge cases for his Parker Bros. 28-gauge double with 30-inch barrels that weighed 6 3/4 pounds.
The first appearance I find of Western Cartridge Co.'s Super-X 28-gauge load with 3/4 ounce of shot, put up in their 2 7/8 inch Field shell is in their March 1, 1931,
Western Ammunition for Rifle, Revolver and Shotgun booklet. With the first printing of their 1932 catalogue, Ithaca Gun Co. was again offering their doubles in 28-gauge, and ran some 28-gauge magazine ads about that time as well --
The first appearance of a 2 3/4 inch 28-gauge shell I find, is the Western Xpert Skeet Load with 3/4 ounce of shot which appears in Western's January 17, 1938, Price List. All three lengths are offered briefly after WW-II. The 2 1/2 inch 28-gauge shells are gone from Western's listings by April 1947, and between the March 1948, and February 1949, editions of the
Western Ammunition Handbook, the Super-X 28-gauge load changes to a 2 3/4 inch case.
