I'm looking to make a keychain out of a reloaded case (no powder), but I want to use an undimpled primer.

So, how would I go about permanently deactivating a primer for this purpose?  I've heard that WD40 works, but only until it dries out.  Is there some way to disassemble the primer so that I just get the "cup"?

Also, what's the best way to permanently fix the primer into the brass?  I don't want it falling out when the keychain gets dropped or well used.

Have you tried this?

Take a fired primer, pop the anvil out.  Then put it on a polished part of a bench anvil, and tap the firing pin back flat with a tight fitting pin punch.

Fired primers are cheap, and they will not blow up in your face.  When you pop the pin mark back out, the primer should swell ever so slightly, and stay seated well in the brass.

Oil of any type will deactivate the primer compound.  After it soaks in you may pop the anvil
out and remove the primer compound disk if you wish.  A small drop of CA in the pocket should help hold the primer in, although friction is usually enough.

you can buy those keychains. I have one in 9mm. Think it was at a gunshow. Try a google search.

I wouldn't trust using a chemically deactivated primer.

You can take a new primer and using something like a dental pick pry out the anvil and the primer compound.  However, it can go off so wearing safety glasses is a must. Then with the primer lying cup down on a flat surface you should be able to push the case over it to seat the primer flush.

Just curious, what caliber were you looking for?

or, you can just shoot the real cartridge, then reload it but dont deprime it or put any power in the case

Priming compound spritzed with WD or any other oil will be stable long enough to be removed with a dental pick.
Just give the oil time to soak in completely before starting to loosen it up.

One question though.
Where are you going to attach the key chain if not the primer pocket?

Keep safe!
S-28

See, I don't trust chemically deactivating the primer.  And I've seen primers go off and imbed themselves 1/4" into wood, so I don't want to play around with a (possibly still) live one.

Anyway, I went ahead and used a dimpled primer.  I tried to knock out the dimple with a hammer and a punch, but it wouldn't go.

I put the brass (.458 SOCOM) in a vise and drilled a hole right through the web, from one side to the other.  Then I used a dremel to clean up the hole.  I then loaded and crimped a 300gr HP.  And finally, I took some jeweler's rouge and polished the brass up.  Tomorrow, I'll go to the craft store and pick out the type of loop I want to go through the brass.

The best way to make a keychain is to remove the primer and stick a nail thru the primer hole  from the inside and with a pair of needle nose pliers bend a ring, put in  the projectile and put the thing on your keychain. Its a durable and more flexible in your pocket unit.
GG

Primers are very funny animals!  Yes you can spray just about anything on them to deactivate on a temp basis.  Again this is only temp.  I've been reloading for longer than I care to remember.  Once the compound dries and set awhile you can still run the risk of having the primer detonate.  This is very dangerous and should not be done at all.  I believe the dummies have a "dummy primer" - one that was never intended to be.  About the only way I'd even think about doing this is to spoon out the inside of the primer until nothing is left but the shell.

Bottom line here is that I'd be very uncomfortable with it.