700.00 dollars
First, it is not a machine gun, regardless of how it is marked. Second, most likely made around the turn of the century.
The National Sewing Machine Company produced the Damascus sewing machine and sold it through Montgomery Wards catalog.
Excelsior double barrel shotguns were made by various Belgian manufacturers c. 1890 - 1914 and I doubt if you will ever be able to identify the exact maker. The crown over the oval ELG indicates it was proofed for black powder after 1893. Damascus is one form of laminated steel, usually considered the best of this type construction, so if it were truly damascus, it would probably be marked as such. 18.0 would be the gauge, I believe that would be a full-choked 12 ga barrel. I doubt if the word below Excelsior would be "Magnum." I don't think that term would have been used for shotgun loads in that time period. Is it possible that it is the remnant of "Machine Made?" The numbers that look like serial numbers MAY actually be serial numbers, but there are no records available that would allow us assign a date of manufacture from them. More likely they are batch numbers or part numbers which could appear on many different guns. The "*M" appearing on the barrels and action are probably assembly marks to indicate that these were "fitted" (parts were not fully interchangeable in those days) and the "Y" possibly the worker who did the final fitting.
Despite the name, it is not a machine gun. Value seldom exceeds 100 USD
Iver Johnson Arms and Cycle Works and J. Stevens Arms. It could be from Simonis, Janssen, Dumouliln and Co. if it is marked 'Machine Made Belgium Damascus Finish'. Some were made by Harrington & Richardson.
If you mean MACHINE guns, the answer is yes.
A graphic cartoon series in 2000s with a robot that has a scarf that's machine gun barrels is the Natsume.
Patrick O'Brien made the first pistol
Sewing Machine 221 Sale website (liked below) specializes in rotary machine manuals.
The original Gatling gun had six to ten barrels which rotated and fired independently. This was one of the earliest machine guns made.
Earlier versions had problems with the lighter barrels overheating.
Made by a machine. Machines never make the same thing EXACLTY the same.