WINCHESTER 52B

Probably you are better off going to a local gunsmith, ask them to take a look in person. You might get lucky and find that Numrich has what you need. Not real clear what screw you are talking about, is it one that holds the action into the stock?

A good smith or machinist can make the screw to fit. You measure the thread count with a thread gauge, these are not expensive and can be found at most industrial supply stores.