Did it once. Over-familiar, whatever. I racked the slide, dropped the mag and then pulled the trigger while pointing it at the floor.
Oops.
Never happened since.
The first, he was holding a 12ga shotgun with the barrel straight up, when it fired. He was in a downstairs apartment. I also knew the people who lived above him. Their 8 year old daughter was sitting on the floor doing her homework on the coffee table. The shot went thru the concrete flooring and it all erupted right under the coffee table. The girl was unhurt.
The second, He was supposedly sitting on his bed cleaning his 357 and it went off. Across the street the neighbor was on his driveway working on the lawnmower. The garage door was open behind him and my friend noticed liquid running down the driveway. He went over to tell his neighbor that he had just plugged the gas tank on his car. His neighbor hadn't even noticed.
Had an accidental discharge at a skeet shoot when my glove caught the trigger while I was waiting for the second house to be reloaded. Scared the piss out of me, luckily the shotgun was pointed down range.
I did the exact same thing when I was a rookie cop. I did not lie. What happened to me? Nothing. Got my ass chewed by the shift lieutenant, that was it.
CC
I am proficient in firearms use and would never 'dry fire' a weapon inside my home while trying to 'practice'.
After cleaning and reassembling a weapon, and after careful inspection, I will pull the trigger, so that the weapon is stored without tension.
The idea of dry firing practice {indoors} is against every safe thing that I have learned about guns for the past 70 years.