In the July 1931 Winchester catalog under Model 21 Extras they state --
"12, 16 and 20 gauge guns can be chambered for 3 inch shells.
In the 1933 Winchester catalog they offer "Chamber for 3 inch shell" for both the Tournament and Trap Grades, but don't mention it under the Standard and Custom Built Grades?
Winchester Catalog 89, 1934, is the same. In the 2000 Proof Loads Model 21 book they state "Any Model 21 can be chambered for 3-inch shells at an extra charge."
The 1940 Winchester pocket catalog in a single paragraph under the Standard Grade first mentions the Model 21 Duck Gun in 12-gauge with 30- or 32-inch barrels chambered for 3" shells.
In the large 1941 catalog the Model 21 Duck Gun was fully listed and described. In that catalog 3" chambering is a $5.55 option for any Model 21. By the 1946 Winchester catalog Chambering for 3" shell was up to $9.75.
The Winchester 81 metal front sight was the standard front sight for Model 21s. Most target guns were standard with a Bradley red bead front sight and Winchester 94 metal middle sight. There were however a plethora of options.
