I believe that this model of shotgun like so many others was made by Crescent Firearms Co.This company made over 100 different Guns which used trademark names for the business that ordered them.Your double barrel shotgun will bring between 100-185 dollars today depending on the overall condition of the shotgun and bores.
Yes.
50-150 USD
That patent date is on several models of Stevens shotguns. Ranger was a trade name sold by Montgomery Ward. It was most likely made sometime between 1920 and 1945.
50-150 USD or so
No
Sold by Sears Roebuck. Probably manufactured by Stevens.
If it is side-by-side, probably Stevens.
Most likely Stevens they did make a model #5100
50-100 USD
100-10000 USD depending on EXACTLY what you have and its condition.
Stevens made for Sears Roebuck
The most consistent answer to this question that I have seen is: Shotguns labeled 'Ranger, Patent April 20, 1915, Proof Tested 12 Gauge' were made by Savage/Stevens Firearms and marketed through Montgomery Ward. However, the design may have begin with Springfield