Who made and how old is a 12ga pump shotgun with a short barrel Riverside Arms Co Chicopee Falls Mass sn 25352 B and under barrel is 5352 with the sign.?

The shotgun you're referring to is likely a model produced by Riverside Arms Co., which was active in the early to mid-20th century, primarily known for making inexpensive firearms. The serial number suggests it was produced around the 1930s or 1940s. Riverside Arms was a trade name used by J. Stevens Arms & Tool Company, and specific details about production dates can vary. For a precise age and valuation, consulting a firearms expert or appraiser with access to historical records would be beneficial.