SD&G seemed to use their Manhattan Arms Co. name on guns from a variety of different sources. My Father use to have a Manhattan Arms Co. 10-gauge that was a very typical Birmingham A&D boxlock. We never knew who actually made the gun and it flowed down the river of commerce long ago. There are also Manhattan Arms Co. marked Hunter Arms Co. Fultons and some really cheap Belgian hammer guns with the Manhattan Arms Co. name stamped on them.
See The Double Gun Journal, Volume Fifteen, Issue 4, pages 101 to 108 for Sauer serial numbers. Looks like your gun would be from the early 1880s.
Last edited by Researcher; 12/11/10 09:49 PM.