I had an AD or Unintentional in early 1990 when I was ordered to decock my Colt Officers ACP at the firing line.
I was on the job for a few months, green as can be. My dad had bought me a COACP for graduation of the police academy in 1988.
I was on the 25-yard line with my Colt at the ready on lane 1. There were officers to my right on each lane waiting for the command to fire.
They were shooting shotguns behind us in another direction.
The range master (Training Sgt) walked up to me and yelled "is that hammer cocked Rookie!"
Before I could finish my response of its a 1911, he was yelling at me to decock. I told him it was a 1911.
He yelled "are you arguing with me.... DECOCK!"
He turned around and began to walk away toward the other lanes.
I carefully thumbed my hammer fwd but being flustered as I just got yelled at, the hammer slipped off my thumb and BANG.
The Colt fired 45 degrees down just forward of me. In my mind (I was fired) but I looked to my right and the officer to my right was still looking forward and the sounds of shotgun blast filled the air.
WOW, I just had an AD and no one ffffnnnnn knew.
This time I doubled thumb my commander style hammer fwd to Condition Two.