I'd bet Parker Bros. was chambering 12-gauge "Pigeon Guns" for 3-inch 12-gauge shells in the 1890s, maybe earlier.
In those days the long shells didn't have a heavier payload. More/better wadding was their feature.
Fred Gilbert Winchester Leaders.jpg
LEADER 12-gauge 3-inch Special Wadding.jpg
The 12-gauge 3-inch progressive burning powder, high velocity loads with 1 3/8 ounce of shot came on the market circa 1924/5 --
Early 12-gauge RECORD Super-X 3-inch.jpg
The 12-gauge 3-inch Magnum load with 1 5/8 ounce of shot came out in 1935, along with Winchester's Model 12 Heavy Duck.
Threaded Mode