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I believe so.  I'm a PLC/controls guy.  I wouldn't even claim hobby level on this type of electronic design.  This is the result LTSpice gave, but I can't say with high confidence that I have everything set up correctly within the software. 

I did alter the name of the IGBT to match the model I used on the real circuit, not to mislead, just to prevent confusion about what IGBT I used in testing.  I've actually used a few different models of IGBT but I don't think its relevant to the issue... just being fully transparent.

Perhaps the simulation sample rate is too slow and makes this look cleaner than it should be.

Thank you for this!  This is exactly the conversation I was hoping to have.  I've thought about this, but I wasn't sure which device would win the "race".  After I read your comment I remembered seeing negative spikes on the oscilloscope during the bench test.  I'm attaching that image from the scope (PWM at near 100%).  R5 was likely 10K during this test so the turn on is very slow, and I think that makes the negative spike more evident.  Is what's shown in this image evidence of what you've described?  Excessive negative Vge?  It looks like about 15 to 20V in the negative direction at each turn-off.  So this would mean I was on the edge during the bench test, and of course destroyed it on the higher voltage machine test.  I believe you've answered the "why?" in my question.  Do you agree based on the image? 

I agree.  This is bad.  My original plan was to cheat the gate drive circuit, so that I could prove out the high voltage/current portion.  If the IGBT held up well with this pitiful gate drive then I planned to go back and use a gate driver IC or better design.  When I realized that high side switching was required for safety aspects on the machine, my cheapo gate drive swerved in to strange territory.  I became a little obsessed with trying to understand why I couldn't get away with it though, especially with that nice simulation taunting me. 

FWIW, I did use a NC relay to ground the IGBT gate if any failure occurred in my microcontroller drive to M1.  That wouldn't help a wire break or similar disconnection though.

I greatly appreciate the input!  Thank you very much for your help!