Originally Posted By: drduc
It is marked 2 3/4" and nickel steel.


It thats the case, the barrel would have been made between 1926 and 1930. 1926 was the first year they made the 20ga. in 2 3/4" and marked the barrels as such(not all were marked). In 1931 they started making the barrels of Winchester Proof Steel.
There should be a year date stamped on the bottom rear of the barrel. It's very hard to see with out total take down.

Ole Cowboy