You will have to try e-gunparts.com, gunshops, gunshows and want ads.
Your Sears model 200 shotgun was made by Winchester.The model 1200 Winchester is the same firearm.
Winchester made the Sears Model 200.
The Sears model 200 is a Winchester Model 1200.
Winchester Model 1200
The Sears 200 is a Winchester Model 1200 with some minor modifications. Winchester 1200 of the same gauge will fit the Model 200 receiver. Buttstock and trigger group will not interchange.
Sears model 200 is Winchester 1200 try your local gunshop.
Probably Mossberg
50-200 usd
200 USD or so
50-200 usd
Winchester