Originally Posted By: Researcher
Quote:
If I recall correctly, the Winchester Model 12 pump was initially introduced as a 2 1/2" 20ga.


But the 12-gauge Model 12 was introduced for 2 3/4 inch shells.


Right. All manufacturers did not convert to 2 3/4" as standard at the same time, and individual manufacturers did not convert all gauges to 2 3/4" at the same time. The above is a perfect example of the last half of that statement.

And that's what makes determining "when did 2 1/2" end?" a complicated question to answer.