1 1/2 frame
 

Measures 1 1/8 in center to center firing pins.

According to the "Dimensions of Gun Barrels at Butt End" on page 47 of theSerialization book, 1 1/8" between firing pins is shared by both the 1 1/2 Frame and the 2 Frame.

Yours appears to be a 1 1/2 Frame with a poor "1/2" stamp.





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Right Dean. I have not seen that before. The stamp for 1/2 one would think would be one piece.

I don't know if it was all included on the same die or if the digits were stamped separately but I tend to think that, judging by the fact that all the 1 1/2 stamps I have ever seen have all been evenly spaced, not cocked or canted, the single die included all the digits.





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Early 1-1/2 frames are marked a 1 followed by a smaller 1 over 2. With no “/“. Like the picture above. The 2 is just missing for some reason.

Later ones were marked “1 1/2”.

Sample
 

Here's a sample from a 1908 DHE. Looks like a one piece stamp to me or a very steady hand indeed.

I’m trying to remember the first year the 1 1/2 frame appeared. I had a 1902 GH that had that frame size stamp with the “/“





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The one pictured is a DH 1903.

Yesterday I had the barrels in my hand and as I turned light through the window reveled a 2 directly below the 1. Strange it can not be seen or felt otherwise only at a certain angle but it is there.