Step 1: Tools and Materials
-Used bullet shell (doesn't really depend on the size)
-Scrap metal (preferable the same type as your shell)
-Small fake diamond
-Solder and flux
Step 2: Cutting the Shell
Step 3: Making the Ring
If you are using a pipe cut a section that is a little wider than the primer end of the bullet shell. For me, the shell was to small to fit anyone so I used a vice to clamp down a solid round piece of metal and hammered the ring on it. This will eventually make the ring bigger until it reaches the size you want.
Now you can start shaping the ring, I used a bench grinder at first, then moved to a file and finished with sand paper. Try to get a nice symmetrical shape and make sure you make it wide enough for the butt of the shell.
Step 4: Fitting the Ring Together
Step 5: Soldering
You may have to do some touch up sanding around the joint.