You mean like this?
Lots of trial and error! I've tried every method under the sun. The best way I've found is to use a .40 and a .45 spent shell casing. Here's how I did the one above:
1. Go to the shooting range and find some spent .45 and spent .40 shell casings (you'll need a bunch of the .40 calibur).
2. take a scrap piece of leather and hammer the .40 casing through it (like a punch). The diameter of the .40 is just perfect to hold the lip of a .45.
3. push the .45 through the hole you just made in the leather.
4. use a dremil with a cutting bit to carefully cut off the "barrel" of the casing (all the way to the bottom arrow in the pic below). be sure to keep the "lip" in tact. You can do this by folding the leather over and pinching it in a vice, or just hold it with your hand (BE CAREFUL!)
5. This will leave you with a "button" shell casing
6. Now take your project and pound a NEW .40 casing through the spot where you want to attach the casing like you did in 1. Be sure to use a new .40 casing as they tend to warp in the process.
7. Push the "button" through the new hole from the back side of the project piece.
8. slobber some glue on the back and if you like add a thin piece of cloth for strength.
9. line the leather to cover up the backside and there you have it.
This gives a nice effect, here's what a finished piece looks like with the shells embedded:
Hope this helps!
