toy's R us I can't match the Coast to Coast mod 660 however Savage, Marlin, Stevens, and Mossberg all sold various models to Coast to Coast and all of them made a pump shotgun. One of these manufactures likely made the mod 660. Find a Gun Values book and try to match the model to the photos.
That is impossible to determine without knowing the manufacturer and model of the shotgun.
It's a Stevens 620.
mossberg
gunparts.com has them
cowbourd
Follow manufacturer's instructions.
At Gunstocks Inc.
@ turn of the century
Savage
We carry new replacement magazines for that shotgun.
Between 1894 and 1930.
can't be done without pictures/