Tam @ The Arms Room writes …
The timing of the Number 2′s launch could not have been more propitious, coming as it did shortly on the heels of the shelling of Fort Sumter. Although it was never officially adopted by the U.S. Army, Yankee soldiers spent their own money ordering them to the point that S&W had to close their order books only a year or two into the war, and the revolver to this day is informally known as the “Old Army” model, despite its lack of official contracts.