The response code for a changed URL is usually in the form of a 301 or 302 response status code. The entire 3xx series of response codes communicate much information that can optionally be acted ...

If Google sees a 302 redirect in place for several months, one would assume Google would change the status of the "temporary" redirect meaning of a 302 status code and treat it more like a 301 ...

A new document from Google explains how HTTP status codes impact a site’s appearance in search results.