I had a Kroil moment this AM. I rounded off the hex setscrew holding the breechface in my SVI slide (yes, you read that correctly - this slide has interchangeable breechfaces) trying to remove it. This setscrew is reached from the rear of the firing pin channel and has a center hole for the firing pin. I have't had this out in ages and it was stuck. When screwed in parts are vibrated they sometimes loosen up and sometime seem to self-tighten. This was the later.
I Kroiled it for an hour or so, then used a hex wrench. I was able to a grip on the socket with and it came out with minor persuasion. The hex socket was rounded, so I replaced the setscrew. The lesson is that if something appears stuck, STOP and go to penetrating oil before you do any damage.
You can see the screw in the back of this image.
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