I had similar partial ignition on a cold range session and I'm done with it also.
Granted my original DISC is not the ideal setup, it had worked fine in warm temps.
December 25 degrees checking zero before season, giving my uncle some loading instruction, 2" fresh snow.
I was able to follow the tracks of the skipping sabot and did find one bullet of the 5 or so misfires.
I have a feeling it was due to the temp and sabot fit of the Hornady's, maybe CCI standard 209 primers also.
