The border selection it's a very tricky way to do it, heres an alternative way (easier) of how you do the metal ring....
Step 1: Make the circle selection using the Ellipse tool (E) and pressing Shift for getting a perfect circle. (don't forget to save it as a path).
Step 2: Create a new transparent layer [Menu Layer>New] OR typing Ctrl+Shift+N OR in the Layer Dock (You get it pressing Ctrl+L) just clik in the New Layer Button.
Step 3: Draw a Blend with the Blend tool (L) Gradient FG to BG, Linear shape and select 2 shades of gray: one medium gray and the other almost white.
Step 4: Now go to [Menu Select>Shrink] and type like 25 or 30 px and accept. Your selection will shrink and let you a metal border outside.
Step 5: Draw the blend again but in opposite direction.
Step 6: Skrink again the selection but now use a minor pixel value.
Step 7: Erase the selection pressing Delete or with the Eraser tool (shift+E)
Hope you find it useful