The value is $40-$150 depending on condition, location, need etc.
Try http://www.canadiangunnutz.com/
Try the internet, gun show, gun shops, want ads.
50-100
Kessler. Only in business from 1951 to 1953.
A Western Field Mod 30 is a Savage Mod 520 Model 30 (based on Stevens/Savage 520) was a pump action shotgun and came in 12 and 16 gauge, but NOT 20 gauge or .410 gauge. Model 30 (based on Kessler model 30C) was a bolt action shotgun and also only came in 12 and 16 gauge. There is some confusion about model 30 Western Fields because there were two very different variations, both pump and bolt action types. If your Western Field shotgun only has "model 30" stamped on it, with no other alpha-numeric designation such as 25EKN or SB526, then it is likely a pump action 12 gauge.
You can get a clip or magazine for a 20 gauge model 228 Kessler shotgun from one of several gun parts catalogs. These include Cheaper Than Dirt and the Numrich catalog.
Model 58 is an automatic not a bolt action
Cant find information on a kessler bolt action rifle from 1950
Winchester made a Model 1887 lever-action shotgun from 1887 - 1899. Norinco currently makes a reproduction of the Model 1887.
45$
The Mossberg model 185D bolt action shotgun was made from 1947-1959.
With the serial number that you have provided,your Winchester model 12 pump action shotgun in 20 gauge was made in the year 1930.