After replacing the entire front panel on one of my cameras today I discovered that this ring can be easily removed, although I doubt if I could have purchased it separately. It looks like I had dropped the camera and knocked this part out of round (see dent on far right), and this was what was preventing the lens from extending.
This type of incident may happen again, so I might as well repair this part so I don’t have to buy it again. But how? It would be nice to have a big metal cone to force this ring onto to get it back into round, but I know of no such thing. So now what?