What did you use? Alloy, flux? The casing is a brass, so it should be rather easy to work with a silver braze. Or you can use a regular soft solder if the loop is anchored on the other side.
If it doesn’t work, mechanically clean the joint area to bare shining metal and use a more aggressive flux. (Then use ultrasonic eyeglass cleaner to get rid of the flux residues.)
More about the brasses used e.g. here:
There are also bullet jewels with hated one’s name on it. I made one on an order, for a friend, from a spent 9mm shell, with engraved name of her ex. (No, he did not get shot.) Didn’t look half bad. No loop though, just a pair of 2mm (2.5mm? Don’t remember) holes at the base and thin leather strip pulled through.
Wrong alloy (you can’t braze resistive wires from a hairdryer heater with silver, it won’t stick - brass works just well, other such combos are for other metals). Wrong flux (the flux is the crucial part there that does the hard job, the filler metal is there only for the party; a wrong one at too low or too high temperature won’t dissolve oxides on the metal you work with, reacts with the metals and coats their surfaces with nonwettable crud, or decomposes and leaves nonwettable deposits). Dirty surfaces. Too little heat (you have to heat the surfaces well enough or even a well-melted filler metal won’t stick).
Try to rule out the four options. My bet is that it’s one of them.
Try to even just wet the metal with the soldering alloy (the filler metal), without adding the other part. If you get a stain well-wetting the base metal, you won and the rest is just getting the mechanics right. I have excellent results with a low-melting silver-copper alloy (don’t ask me which one it is, but it melts quite below 700 'C), using either borax as flux (cheap, plentiful, decent) or a sodium tetrafluoroborate based commercial flux (more expensive, easy-ish to find in Home Depot style stores), at dark cherry red heat using a small torch.
(You’re supposed to gently wiggle off the bullet, pour out the propellant, discharge the primer by e.g. firing it in a gun, and then and only THEN apply heat. )
Ever been to etsy? Search results: “bullet” (35,686 Results)
Maybe it isn’t your thing, but there is a lot of jewelry, bottle openers, pens, key chains, cigar punches, etc made from or look like bullets. Hell there was a company that makes .50cal bottle openers that got a deal on Shark Tank.
+1.
I used the brass base of a 12-bore cartridge as an earring for a while. Clip the plastic case off, polished and lacquered it to prevent it going green and manky, secure with suitable sized o-ring.
ETA: the stuff in the OP isn’t my thing, but I can see the attraction in a grim-and-tasteless way, particularly if the deceased was shot. Wonder if they do other options, like memorial bottles of booze, cigarette lighters or cheeseburgers…
Todo: try that trick with laser-etching of stainless steel, using either fine plaster of paris in alcohol, or molybdenum disulfide lubricant spray. (Deposit a layer of such material on top of the stainless steel, run through with the laser, and the material reacts with the metal, leaving a permanent mark. Laser-assisted chemical reaction can help you when a laser alone wouldn’t cope. I wonder if this could be done with copper, what material could be used to convert a fairly thick layer (think 18-micrometer circuitboard) to something soluble. Would allow avoiding the etching step.)
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