I am getting severe bullet set back with Georgia Arms Gold Dot HP 124 +P. The kahr is new to me, but doesn't have any issue with the FMJ rounds I have, also from Georgia Arms.

Any ideas? Anyone else using this ammo? I am wondering if I received a bad batch of ammo as it seems to set back in the case very easily.

I would call them and ask them to replace ammo. It should not happen and could have nasty results such as blown out cases or worse.

They replaced it, but I still have the original. Now I need a press and some dies to properly crimp the original rounds.

You probably couldn't crimp the cases at this stage.
All you could use would be a taper-crimp die which wouldn't correct the problem you're having.

The only thing you might do is resize the brass but that would require a lot of bullet pulling..etc.
Then you would have to discard the powder (you don't know what it is) and reload the rounds.
You really don't have many options.
At least they replaced the bad ammo. That's good.

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Where are we going and why am I in this hand-basket?