Virtually impossible to tell the calibre of any weapon by just the serial number
It would just be called a Forehand Arms Single Shot.
Forehand and Wadsworth (Forehand Arms) was in business from 1871 to 1902. Unfortunately, there are no serial number records for this company that has been closed for 116 years.
Forehand Arms was the successor company to Forehand & Wadsworth. They were in operation from 1890 to 1902. Not aware of any serial number database for them. Sorry.
You just read it.
Blue Book of Gun Values
Spelled Forehand Arms- and depends on the model and condition. You need a hands on appraisal.
Hopkins and Allen purchased Forehand Arms in 1902, so sometime between then and 1915 when the company closed.
Hopkins and Allen took over the Forehand name in 1903 and continued until 1915.
The other way around I believe. Hopkins and Allen bought Forehand in 1903 and continued producing Forehand guns for a few years.
Hopkins & Allen Arms Co. Fifty Years of Gunmaking 1867 - 1917 by Joseph T. Vorisek is about the best book on H&A.
No published sn data
Forehand & Wadsworth changed their name to Forehand Arms Co. and was eventually taken over by Hopkins & Allen. Unfortunately without the serial number it is hard to narrow down an exact age. I can tell you it was produced between 1887 and 1915.