Mauser, I am well aware of what to do, and not to do, with a squib round. There was no aubible pop. Nothing discernible through ear pro, and not even good ear pro at that. I am aware that a squib will not cycle the slide of a semi and there is little danger there. I am aware that it could push out and possibly clear the cylinder in a revolver, meaning an obstructed barrel and kaboom if you kick off another round behind it.
Again there was no audible pop, and at first I honestly thought it was a misfire. Remedial action for a semi is tap, rack, bang. Remedial action for a revolver, barring an audible pop with no recoil, is to pull the trigger again. There was no audible pop because the primer didnt push the bullet more than 1/16th of an inch, no gas, nor any sound, escaped. Likely because of a heavy crimp, large (for a pistol) case volume, a heavier (158gn) projectile, and a soft (federal) primer that bulged out. Looking at it now the primer was what was hanging the cylinder up on the second trigger pull.
I understand your concern, i appreciate it, and I don't want to come off as a jerk. I know there are enough people on here that are new to this sport and need coaching on basics at time. I assure you I am not in the habit of pulling the trigger all casual like... But remedial action for a revolver in any professional training, and I've been to more than 2 or 3, is to pull the trigger again. With, of course, the caveat that you immediately stop shooting if you hear an audible pop with reduced recoil.