The R flag means the request will redirect to a new URL. You don't actually want a redirect to a new URL, but having the redirect there (temporarily) allows you to see what that URL would be, what path is requested and what parameters are attached.
Look at that URL in the URL bar of the browser. Does that URL contain all the right path and parameter data? It doesn't matter if content is served or not, you just look at the URL itself to see if it is malformed.