I made a recent observation on a couple of top action hammer guns. What appears to be the frame size stamped on the bottom of the frame under the trigger plate. Below are photos of a 3 frame and 4 frame with markings in this location with those corresponding numbers.
3 frame in 39,000 range
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4 frame in 38,000 range
IMG_3627.jpg
Both of these guns are within bout 1,000 serial numbers from each other. Both made in 1884.
I went through my parts bins and the closest numbers I have on either side of these is 26,704 (2 frame) and 45,934 (0 frame). Neither of those had these markings and I have no others on hand that do.
I will continue to keep an eye out for other examples of this and their serial numbers. If anyone else can check their frames and report back, it would be appreciated.
The numbers I listed above exhibit a 19,000 serial number gap representing manufacturing from 1882 to 1885. I would like to try and find examples to be able to narrow that down some.