Bottomline, he pulled the trigger without clearing the gun. Even it's a revolver, any idiot can see if it's loaded or not. Last person handling the gun is responsible. Plus he lied his ass off. He broke every firearm safety rule in the book.
Many people have never fired a gun. He hired a gun expert. Revolvers on a movie set have dummy bullets in them so you can see them when the camera is dead on the revolver. That's how Bruce Lee's kid got killed. They had bullets in the cylinder minus the cartridge. When blanks were added they pushed the bullets out with enough velocity to kill.
Yes, in movies firearms are pointed at actors and the trigger is pulled. They are props and they have a safety guy on set to ensure safety. Why they used a real gun is insanity. No live ammo should be on set. When a gun "expert" is on set they are supposed to hand it to the actor and open the action show it's empty or use a gun with the firing pin or striker removed.
In real life here's a few safety rules.
1. Treat all guns as if they are loaded even if you know they are unloaded. So many accidental firings are from people that said, I thought the gun was unloaded.
2. Never point the barrel at another or yourself. Only point a gun at a threat or a target. A good rule is to imagine a laser is coming out of the barrel. This will keep you conscience about where the gun is pointed.
3. Keep your finger off the trigger until you want to fire the gun. These new striker fired semi autos have a light tap to set off the gun. Also be very careful holstering a fire arm. The trigger can be hit if you're not careful.
On a side note isn't anabolic steroids a schedule felony drug? How can all you steroid users be in possession of firearms when you have syringes and vials in your house? Are you getting them from questionable doctors from a life extension clinics to be "legal".