An ORIGINAL Winchester Rear Sight No 22A. This was called the Rocky Mountain Flat top that had a wide base. The height of the flat top is 0.337 inches. The sight was used on 1866, 1873, 1876,1886, 92, 94 and 95 rifles; was also specific to No 4 and 5 barrels. This was replaced by the 22D in 1924 and was used through 1932 when it went obsolete. The No 1 elevator is correct for this sight.
