This really applies to North American ammunition manufacturers. I don't know how the history of long 20-gauge shells went in Europe.
The 3-inch
Magnum 20-gauge was a mid-1950s item. The first commercial listing for a 3-inch magnum 20-gauge that I've found, was the Magnum Model 21 in the January 2, 1954, Winchester catalogue. However, there are no 3-inch 20-gauge shells listed in the January 2, 1954, Winchester Ammunition catalogue and price list, but they are in the January 2, 1954, Western Cartridge Co. catalogue and price list. The story goes that the Olin brothers and their buddies had been playing around with 3-inch 20-gauge Model 21s for some time before that. In the 1954 Western Cartridge Co. ammunition catalogue the 20-gauge 3-inch Mag. is offered with 1 1/8 ounce of Lubaloy #6 or 1 3/16 ounce of Lubaloy #4. The next year the 2 3/4 inch "magnum" shells were introduced with 1 1/2 ounce in 12-gauge, 1 1/4 ounce in 16-gauge and 1 1/8 ounce in 20-gauge. The 3-inch 20-gauge Mag. offerings remained the same through the 1959 price list. For 1960 the 3-inch 20-gauge magnum with 1 1/4 ounce of chilled shot was added to the offerings, while the Lubaloy loads were still 1 1/8 and 1 3/16. The Winchester/Western offerings in 3-inch 20-gauge shells remained the same thru 1968 where my old catalogues play out.
As we've discussed above, long shotgun shells have been around since the late 1890s. In the first 35 years of the 20th Century there were a plethora of shell lengths. In my 1903 UMC catalogue there were 12-gauge paper shells 2 5/8, 2 3/4, 2 7/8, 3 and 3 1/4 inch. The 16-gauge was available 2 9/16, 2 3/4, 2 7/8, and 3 inch. The 20-gauge was offered in 2 1/2, 2 3/4, 2 7/8, and 3 inch. The “standard” shell, 2 5/8 inch 12-gauge, and 2 ˝ inch 20-gauge carried slightly milder loads than the max offered in the 2 ľ inch shells, but the 2 7/8, 3-inch and longer shells just got more wadding, which many serious Pigeon shooters thought to be an advantage.
In the 20-gauge, the maximum loads offered in the "standard" 2 1/2 inch case were 2 1/4 drams of bulk smokeless powder or 18 grains of dense smokeless powder such as Ballistite or infallible pushing 7/8 ounce of shot. In the 2 3/4 inch and longer 20-gauge cases one could get 2 1/2 drams of bulk smokeless powder or 20 grains of Ballistite or Infallible pushing that same 7/8 ounce of shot a bit faster.
These were the shells for the famous Widgeon Duck Club Parker Bros. 3-inch 20-gauge guns and the J. Stevens Arms & Tool Co.'s No. 200 pump.
The only one of the ammunition companies I’ve found to offer long shells with their new progressive burning powder high velocity loads was Peters, and just like the old bulk or dense smokeless powder shells, the 2 7/8 and 3-inch Peters High Velocity shells didn’t carry a heavier payload, just more wadding –
From the 1927 Peters catalogue –
I believe much of the talk or the 3-inch 16-gauge shells come from Stadt's mentioning of them in conjunction with Winchester Model 21s. In the 1934 Winchester Catalog 89, Winchester offers their Leader shell in extra length hulls, both 2 7/8 and 3-inch in 12-, 16- and 20-gauges, but the maximum 16-gauge load offered in the Leader 16-gauge shell is 2 3/4 drams of bulk smokeless powder and 1 ounce of shot. Meanwhile in their progressive burning powder Super-Speed 16-gauge shells one could get 1 1/8 ounce of shot in either a 2 9/16 or 2 3/4 inch hull?!? Leader 3-inch 16-gauge shell --
FWIW, I’ve reviewed the production cards for the graded Ansley H. Fox 16-gauge guns and found a total of nine ordered chambered for 3-inch shells and one ordered chambered for 2 7/8 inch shells.
